CN111654842B

CN111654842B - Terminal device, communication control method, and communication control device

Info

Publication number: CN111654842B
Application number: CN202010466252.9A
Authority: CN
Inventors: 木村亮太; 内山博允; 泽井亮; 古市匠; 高野裕昭; 津田信一郎
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2013-04-10
Filing date: 2014-01-31
Publication date: 2024-01-30
Anticipated expiration: 2034-01-31
Also published as: WO2014167883A1; JP6398970B2; EP3627920B1; EP3627920A1; EP2986072A1; US20200045580A1; CN111654842A; US20160021566A1; US10499277B2; BR112015025271A2; EP2986072A4; AU2014252012A1; AU2014252012B2; JPWO2014167883A1; CN105075367A; US11206573B2; EP2986072B1

Abstract

The invention relates to a terminal device, a communication control method, and a communication control device. In order to suppress an increase in load on a base station when inter-device communication is performed, a terminal device capable of communicating with the base station is provided with: an acquisition unit that acquires radio resource information on radio resources usable for inter-device communication not via a base station among radio resources controllable by the base station; and a decision unit that decides a size of data to be transmitted/received in inter-device communication based on the radio resource information.

Description

Terminal device, communication control method, and communication control device

The present application is a divisional application of chinese patent application 201480019560.X filed on 1 month 31 of 2014, entitled "terminal device, communication control method, and communication control device".

Technical Field

The present disclosure relates to a terminal device, a communication control method, and a communication control device.

Background

In recent years, cellular communication systems such as Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) have been widely popularized. In addition, data traffic in communication systems is increasing due to the popularity of smartphones and the like. Thus, it is becoming increasingly important for individual communication providers to increase the communication capacity of the communication system.

In addition, in response to an increase in data traffic, inter-device (D2D) communication may also be considered for offloading data. For example, when two terminal apparatuses communicate directly with each other, not through a base station, the data traffic of wireless communication via the base station can be reduced, thereby reducing the load on the network side including the base station.

For example, a technique of using a wireless terminal as a relay station for multi-hop communication and allocating wireless resources (slots) to the multi-hop communication is disclosed (for example, see JP 2004-248210A). In addition, a technique is disclosed that uses a wireless terminal as a relay station of an ad-hoc network, and allows the wireless terminal to directly communicate with a base station when it is determined that the amount of data in the ad-hoc network exceeds the amount of transmittable data (for example, see JP 2009-89042A).

CITATION LIST

Patent literature

Patent document 1: JP 2004-248210A

Patent document 2: JP 2009-89042A

Disclosure of Invention

However, when D2D communication is introduced, the load of the base station increases.

Specifically, in a cellular communication system represented by LTE, in communication between a base station and a terminal device, the base station determines the size of data to be transmitted using allocated radio resources in both uplink and downlink. For example, the third generation partnership project (3 GPP) technical standard TS36.213 describes a method of determining the size. However, the decision method is a method for communication between the base station and the terminal device, in which D2D communication is not considered.

Then, as in the case of communication between the base station and the terminal device, it is considered that in D2D communication, the base station also decides the size of data. However, when determining the size of data as in the case of communication between a base station and a terminal device, the base station is to collect various information related to D2D communication (e.g., information related to Medium Access Control (MAC), radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP)). As a result, the overhead of the base station for information collection increases. Further, a heavy burden is imposed on the base station due to management and control of D2D communication. In this way, there is a concern that the load of the base station increases.

It is therefore desirable to provide a system capable of suppressing an increase in load of a base station when inter-device communication is performed.

According to the present disclosure, there is provided a terminal device capable of communicating with a base station, the terminal device comprising: an acquisition unit that acquires radio resource information on radio resources available for inter-device communication not via the base station among radio resources controllable by the base station; and a decision unit that decides a size of data to be transmitted and received in inter-device communication, based on the radio resource information.

According to the present disclosure, there is provided an information processing apparatus that controls a terminal apparatus capable of communicating with a base station, the information processing apparatus including: a memory for storing a predetermined program; and a processor capable of executing the predetermined program. The predetermined program is for performing the following operations: obtaining radio resource information on radio resources available for inter-device communication not via the base station among radio resources controllable by the base station, and determining a size of data to be transmitted and received in the inter-device communication based on the radio resource information.

According to the present disclosure, there is provided a communication control apparatus of a base station, the communication control apparatus including: an allocation unit that allocates, from among radio resources controllable by the base station, radio resources for radio communication between the base station and the terminal device to the terminal device; and a notifying unit that notifies the terminal device of available radio resources among the radio resources controllable by the base station. Some or all of the available radio resources are used for inter-device communication not via the base station. The size of data to be transmitted and received in inter-device communication is not determined by the base station but by the terminal device capable of communicating with the base station.

As described above, according to the present disclosure, it is possible to suppress an increase in load of a base station when inter-device communication is performed.

Drawings

Fig. 1 is an explanatory diagram illustrating radio resources in the time direction of FDD.

Fig. 2 is an explanatory diagram illustrating radio resources with respect to a time direction of TDD.

Fig. 3 is an explanatory diagram illustrating an example of the structure of the link direction defined in 3 GPP.

Fig. 4 is a sequence diagram illustrating an example of a schematic flow of communication control processing for communication between a base station and a terminal device.

Fig. 5 is an explanatory diagram illustrating an example of specific contents of a candidate Transport Block Size (TBS).

Fig. 6 is an explanatory diagram illustrating specific content of CQI.

Fig. 7 is an explanatory diagram illustrating a correspondence relationship between MCS index and TBS index for PDSCH.

Fig. 8 is an explanatory diagram illustrating a correspondence relationship between MCS index and TBS index with respect to PUSCH.

Fig. 9 is an explanatory diagram illustrating an example of a schematic structure of a communication system according to an embodiment of the present disclosure.

Fig. 10 is an explanatory diagram illustrating an example of wireless communication in the case where a Local Network (LN) is employed as one form of D2D communication.

Fig. 11 is an explanatory diagram illustrating an example of wireless communication in a case where individual D2D communication is adopted as one form of D2D communication.

Fig. 12 is an explanatory diagram illustrating an outline of the first embodiment.

Fig. 13 is a block diagram illustrating an example of the functional structure of the terminal device according to the first embodiment.

Fig. 14 is an explanatory diagram illustrating an example of D2D resources.

Fig. 15 is an explanatory diagram illustrating an example of a control channel transmitting size-related information.

Fig. 16 is an explanatory diagram illustrating an example of a data channel transmitting size-related information.

Fig. 17 is a sequence chart illustrating a first example of a schematic flow of the communication control process according to the first embodiment.

Fig. 18 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the first embodiment.

Fig. 19 is a flowchart illustrating a first example of a schematic flow of a process of deciding a size of data to be transmitted and received in D2D communication.

Fig. 20 is a flowchart illustrating a second example of a schematic flow of a process of deciding a size of data to be transmitted and received in D2D communication.

Fig. 21 is a flowchart illustrating a third example of a schematic flow of a process of deciding a size of data to be transmitted and received in D2D communication.

Fig. 22 is a flowchart illustrating a fourth example of a schematic flow of a process of deciding a size of data to be transmitted and received in D2D communication.

Fig. 23 is a flowchart illustrating a fifth example of a schematic flow of a process of deciding a size of data to be transmitted and received in D2D communication.

Fig. 24 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the first embodiment.

Fig. 25 is a flowchart illustrating an example of a schematic flow of a process of determining the size of data to be transmitted and received in D2D communication.

Fig. 26 is a sequence diagram illustrating an example of a schematic flow of the communication control process according to the second modification of the first embodiment.

Fig. 27 is a flowchart illustrating an example of a schematic flow of a process of allocating radio resources for D2D communication between slave devices in the second modification of the first embodiment.

Fig. 28 is a flowchart illustrating an example of a schematic flow of a process of deciding the size of data to be transmitted and received in D2D communication between slave devices in the second modification of the first embodiment.

Fig. 29 is a sequence diagram illustrating an example of a schematic flow of the communication control process according to the third modification of the first embodiment.

Fig. 30 is a sequence chart illustrating a first example of a schematic flow of communication control processing according to a fourth modification of the first embodiment.

Fig. 31 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the fourth modification of the first embodiment.

Fig. 32 is an explanatory diagram illustrating an outline of the second embodiment.

Fig. 33 is a block diagram illustrating an example of the functional structure of a terminal device according to the second embodiment.

Fig. 34 is a sequence chart illustrating a first example of a schematic flow of the communication control process according to the second embodiment.

Fig. 35 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the second embodiment.

Fig. 36 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the second embodiment.

Fig. 37 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to a second modification of the second embodiment.

Fig. 38 is a sequence chart illustrating a first example of a schematic flow of communication control processing according to a third modification of the second embodiment.

Fig. 39 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the third modification of the second embodiment.

Fig. 40 is a sequence chart illustrating a third example of a schematic flow of the communication control process according to the third modification of the second embodiment.

Fig. 41 is an explanatory diagram illustrating an outline of the third embodiment.

Fig. 42 is a block diagram illustrating an example of the functional structure of a terminal device according to the third embodiment.

Fig. 43 is a sequence diagram illustrating an example of a schematic flow of the communication control processing according to the third embodiment.

Fig. 44 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the third embodiment.

Fig. 45 is a sequence diagram illustrating a first example of a schematic flow of communication control processing according to a second modification of the third embodiment.

Fig. 46 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the second modification of the third embodiment.

Fig. 47 is a first explanatory diagram illustrating the position of RLC in L2 of LTE.

Fig. 48 is a second explanatory diagram illustrating the position of RLC in L2 of LTE.

Fig. 49 is a flowchart illustrating an example of a schematic flow of processing of RLC when D2D communication is employed.

Fig. 50 is an explanatory diagram illustrating the maximum number of HARQ processes related to the downlink of TDD.

Fig. 51 is a flowchart illustrating an example of a schematic flow of control processing when the maximum number of HARQ processes is set in each of normal wireless communication and D2D communication.

Fig. 52 is a flowchart illustrating an example of a schematic flow of control processing when the maximum number of HARQ processes is set in both normal wireless communication and D2D communication.

Fig. 53 is a flowchart illustrating an example of a schematic flow of control processing when no HARQ process is generated for D2D communication.

Fig. 54 is a block diagram illustrating an example of a schematic structure of a smart phone.

Fig. 55 is a block diagram illustrating an example of a schematic structure of the in-vehicle navigation apparatus.

Fig. 56 is a block diagram illustrating an example of the functional structure of a base station according to the reference embodiment.

Fig. 57 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the reference embodiment.

Fig. 58 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the reference embodiment.

Fig. 59 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the second modification of the reference embodiment.

Fig. 60 is a block diagram illustrating a first example of a schematic structure of an eNB.

Fig. 61 is a block diagram illustrating a second example of a schematic structure of an eNB.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that in the specification and drawings, constituent elements having substantially the same functions and structures are denoted by the same reference numerals, and repetitive description thereof is omitted.

Note that description will be made in the following order:

1. introduction to the invention

Techniques for wireless communication in 1.1.3GPP

1.2. Technical problem

2. Schematic structure of communication system according to embodiment of the present disclosure

3. First embodiment

3.1. Overview

3.2. Functional structure of terminal equipment

3.3. Flow of processing

3.4. First modification example

3.5. Second modification example

3.6. Third modification example

3.7. Fourth modification example

4. Second embodiment

4.1. Overview

4.2. Functional structure of terminal equipment

4.3. Flow of processing

4.4. First modification example

4.5. Second modification example

4.6. Third modification example

5. Third embodiment

5.1. Overview

5.2. Functional structure of terminal equipment

5.3. Flow of processing

5.4. First modification example

5.5. Second modification example

6. Related peripheral operations

7. Application example

8. Summary

9. Reference examples

9.1. Overview

9.2. Functional structure of base station

9.3. Flow of processing

9.4. First modification example

9.5. Second modification example

9.6. Application example

< introduction >

Referring first to fig. 1-8, techniques of wireless communication in 3GPP, and technical problems are described.

< technique of Wireless communication in 1.1.3GPP >

Referring to fig. 1-8, techniques for wireless communication in 3GPP are illustrated.

(radio resources and Format)

-time direction

In wireless communication in 3GPP, radio resources are divided in a time direction. For example, in LTE, radio resources are divided in units of subframes. This will be described below with reference to fig. 1 and 2.

Fig. 1 is an explanatory diagram illustrating radio resources with respect to a time direction of Frequency Division Duplex (FDD). Referring to fig. 1, 10 subframes included in a radio frame of 10ms are shown. In FDD, a frequency band for uplink and a frequency band for downlink are prepared, and resource control is performed in units of subframes in each frequency band. Note that each subframe contains two slots. Furthermore, each slot contains 7 Orthogonal Frequency Division Multiplexing (OFDM) symbols.

Fig. 2 is an explanatory diagram illustrating radio resources with respect to a time direction of Time Division Duplexing (TDD). Referring to fig. 2, 10 subframes included in a radio frame of 10ms are shown. In TDD, communication is performed in a link direction in units of subframes. That is, each subframe is one of a downlink subframe, an uplink subframe, or a special subframe. The special subframes are set to suppress interference when switching from the downlink subframes to the uplink subframes. The special subframe includes a downlink pilot time slot (DwPTS), a guard interval, and an uplink pilot time slot (UpPTS). Referring to fig. 3, a specific example of the link direction in the subframe unit in TDD is described below.

Fig. 3 is an explanatory diagram illustrating a configuration example of a link direction defined in 3 GPP. Referring to fig. 3, 7 configurations defined in the LTE technical standard (TS 36.211 table 4.2-2) are shown. The subframe denoted by "D" is a downlink subframe, the subframe denoted by "U" is an uplink subframe, and the subframe denoted by "S" is a special subframe. For example, in LTE, any of these 7 configurations is selected and applied.

-frequency direction

In addition, for example, in LTE, radio resources are also divided in the frequency direction. Specifically, in the band direction, subcarriers exist at 15kHz intervals. The subcarriers are then packetized every 12 subcarriers (i.e., 180 kHz).

-time direction and frequency direction

For example, in LTE, radio resources within 12 subcarriers in the frequency direction and 1 slot in the time direction are regarded as Resource Blocks (RBs). Further, the radio resources of 1 subcarrier and 1 OFDM symbol are referred to as resource elements.

Each RE is used for transmission of control signals or data signals. Examples of the control signal include a synchronization signal, a reference signal, and the like.

Further, a channel is defined that includes one or more resource elements. In LTE, as channels of a downlink, a Physical Downlink Control Channel (PDCCH), a physical downlink shared channel (PBCH), a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), and a Physical HARQ Indicator Channel (PHICH) are defined. On the other hand, as uplink channels, a Physical Uplink Control Channel (PUCCH), a Physical Uplink Shared Channel (PUSCH), and a Physical Random Access Channel (PRACH) are defined.

Note that basically, data is transmitted on PDSCH in downlink and PUSCH in uplink. The number of REs available for transmission of data affects the size of the data to be transmitted and received.

(communication control processing for communication between base station and terminal device)

In a cellular communication system represented by LTE, in communication between a base station and a terminal device, the base station determines the size of data to be transmitted using allocated radio resources in both uplink and downlink. Specifically, the base station determines an arbitrary predetermined Transport Block Size (TBS) as the size of data to be transmitted. An example of communication control processing for communication between a base station and a terminal device is described below with reference to fig. 4.

The terminal device feeds back information on a channel between the base station and the terminal device periodically or according to an instruction of the base station (S1001). For example, the information is channel related information including a Channel Quality Indicator (CQI), a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), a Reference Signal Received Power (RSRP), a Reference Signal Received Quality (RSRQ), and the like. The channel state information relates to a modulation scheme and a coding scheme used for communication between the base station and the terminal device.

When downlink data delivered to the terminal device is generated or when the terminal device requests a transmission opportunity, the base station performs resource control for communication between the base station and the terminal device (S1003). Specifically, the base station allocates radio resources for communication between the base station and the terminal device. In LTE, the radio resources are RBs.

The base station then decides the size of data transmitted and received using the allocated radio resources after the resource control (S1005). This size is referred to as the Transport Block Size (TBS). Since the candidate TBSs are determined in LTE, the base station then decides any candidate corresponding to the allocated radio resource among the candidate TBSs as the size of data to be transmitted and received.

Thereafter, the base station notifies the terminal device of control information including information on the allocated radio resources and the decided size (S1007). The information on the downlink is notified to the terminal device in the form of downlink allocation and the information on the uplink is notified to the terminal device in the form of uplink access grant. Specifically, the PDCCH includes Downlink Control Information (DCI), which includes a Modulation and Coding Scheme (MCS) index. The MCS index corresponds to the TBS index, and the modulation scheme and the coding scheme. Then, the terminal device obtains the TBS index from the MCS index and obtains the TBS from the TBS index and the number of allocated RBs. The terminal device obtains the modulation scheme and the coding scheme to be used from the MCS index.

The base station and the terminal apparatus then transmit and receive data having a predetermined size using the allocated radio resources (S1005).

(various information related to the determination of data size)

-candidates for Transport Block Size (TBS)

As described above, the base station decides any candidate corresponding to the allocated radio resource among the candidate TBSs as the size of data to be transmitted and received. In addition, the terminal device obtains the decided TBS from the TBS index and the number of allocated RBs. The details of the TBS are described below with reference to fig. 5.

Fig. 5 is an explanatory diagram illustrating an example of specific contents of a candidate Transport Block Size (TBS). Referring to fig. 5, a table of candidate TBSs specified in table 7.1.7.2.1-1 of 3GPP technical standard TS26.213 is shown. The candidate TBS corresponds to the TBS index and the number of RBs. As TBS indexes, 27 indexes are defined, and as the number of RBs, 1 to 110 PB are defined. The base station decides any candidate in the candidate TBSs as the size of data to be transmitted and received according to the number of allocated RBs, modulation scheme, coding scheme, and the like. For example, the base station selects one column of the table corresponding to the number of RBs according to the number of allocated RBs. The base station then decides any candidate of the candidate TBSs included in the selected column as the size of data to be transmitted and received according to the modulation scheme, the coding scheme, and the like.

-CQI

As described above, the terminal measures the communication quality of the downlink, which is reported to the base station in the form of CQI. The specific content of CQI will be described below with reference to fig. 6.

Fig. 6 is an explanatory diagram illustrating specific content of CQI. Referring to fig. 6, a table of CQI specified in table 7.2.3-1 of 3GPP technical standard TS36.213 is shown. CQI is one of 1-15. Each CQI corresponds to a modulation scheme, a coding rate, and bits/symbol.

MCS index and TBS index

As described above, the MCS index corresponds to the TBS index. The details of this are described below with reference to fig. 7 and 8.

Fig. 7 and 8 are explanatory diagrams illustrating the correspondence between MCS indexes and TBS indexes. Referring to fig. 7, a table for correspondence between MCS index and TBS index for PDSCH specified in table 7.1.7.1-1 of 3GPP technical standard TS36.213 is shown. Further, referring to fig. 8, a table of correspondence between MCS index and TBS index for PUSCH specified in table 8.6.1-1 of 3GPP technical standard TS36.213 is shown. In this way, the terminal device can obtain the TBS index from the MCS index among the DCIs included in the PUCCH. Subsequently, as shown in fig. 5, the terminal device may obtain a TBS according to the TBS index and the number of PB.

<1.2. Technical problem

As described above, the size of data to be transmitted and received in communication between the base station and the terminal device is determined. However, when inter-device communication (i.e., D2D communication) is introduced in addition to such communication, the load on the base station increases.

Specifically, in a cellular communication system represented by LTE, a base station determines the size of data to be transmitted using allocated radio resources in both uplink and downlink in communication between the base station and a terminal device. As described above, for example, the third generation partnership project (3 GPP) technical standard TS36.213 describes a method of determining the size. However, the decision method is a method for communication between the base station and the terminal device, in which D2D communication is not considered.

Then, as in the case of communication between the base station and the terminal device, it is considered that in D2D communication, the base station also determines the size of data. However, when determining the size of data as in the case of communication between the base station and the terminal device, the base station is to collect various information related to D2D communication (e.g., information related to MAC, RLC, and PDCP). As a result, the overhead of the base station for information collection may increase. Furthermore, heavy load is imposed on the base station due to management and control of D2D communication. In this way, the load of the base station may increase.

Thus, the embodiments of the present disclosure can suppress an increase in load of the base station in the case of performing D2D communication.

Schematic structure of communication System according to embodiments of the present disclosure

Subsequently, with reference to fig. 9 to 11, a schematic structure of a communication system according to an embodiment of the present disclosure is explained. Fig. 9 is an explanatory diagram illustrating an example of a schematic structure of a communication system according to an embodiment of the present disclosure. Referring to fig. 9, the communication system 1 comprises a base station 10, a core network entity 20 and a terminal device 100. For example, the communication system 1 is an LTE compliant system.

(base station 10)

The base station 10 controls wireless communication of the base station 10 within the cell 11. For example, the base station 10 performs wireless communication with the terminal device 100 placed in the cell 11, and controls the wireless communication. For example, the base station 10 is an eNodeB. For example, the base station 10 performs wireless communication using one of FDD and TDD. For example, the base station 10 performs radio communication using OFDM in the downlink, and performs radio communication using single carrier frequency division multiple access (SC-FDMA) in the uplink. The base station 10 can perform wireless communication with the terminal device 100 through a relay station.

For example, the base station 10 allocates radio resources for radio communication between the base station 10 and the terminal device 100 to the terminal device 100. Specifically, for example, the base station 10 allocates radio resources to the terminal device 100 for downlink transmission of data delivered to the terminal device 100. Further, the base station 10 allocates radio resources to the terminal device 100 for downlink transmission of data delivered to the terminal device 100. Further, the base station 10 allocates radio resources to the terminal device 100 for uplink transmission of data delivered to the terminal device 100. Note that the base station 10 includes a resource allocation unit that allocates radio resources in this way.

Further, for example, radio resources are allocated in predetermined division units. Specifically, for example, radio resources are allocated in subframe units in the time direction and in resource block units (i.e., 12 subcarrier units) in the frequency direction.

Note that the base station 10 may not allocate any radio resource to any terminal to suppress interference.

(core network entity)

The core network entity 20 is an entity arranged in a core network 21. For example, the core network 21 is an Evolved Packet Core (EPC), the core network entity 20 is a Mobility Management Entity (MME), a serving gateway (S-GW), a packet data network gateway (P-GW), and the like. The core network entity 20 performs control related to wireless communication between the base station 10 and the terminal device 100.

(terminal device 100)

The terminal device 100 is a device capable of communicating with the base station 10. For example, the terminal device 100 is a device that allows wireless communication with the base station 10. Specifically, for example, when placed in the cell 11, the terminal device 100 performs wireless communication with the base station 10. For example, the terminal device 100 performs wireless communication according to one of FDD and TDD. Further, for example, the terminal device 100 performs wireless communication using OFDM in the downlink and performs wireless communication using SC-FDMA in the uplink. The terminal device 100 can perform wireless communication with the base station 10 via the relay station.

For example, the terminal device 100 performs wireless communication with the base station in accordance with the control of the base station 10. Specifically, for example, the terminal device 100 performs wireless communication in the uplink or the downlink using the wireless resources allocated to the base station 10.

In particular, in the embodiment according to the present disclosure, the terminal device 100 performs inter-device communication (i.e., D2D communication) with another terminal device 100 using a part of radio resources controllable by the base station 10. As described above, the radio resources controllable by the base station 10 are, for example, radio resources allocable by the base station 10. Further, for example, when a different radio access scheme is used between the downlink and the uplink, the terminal device 100 performs D2D communication using one of the uplink radio access scheme and the downlink radio access scheme. Specifically, for example, the terminal device 100 performs D2D communication using DFDM, or performs D2D communication using SC-FDMA. Here, as a form of D2D communication, a Local Network (LN) and individual D2D communication are considered. Specific examples of these points are described below with reference to fig. 10 and 11.

Fig. 10 is an explanatory diagram illustrating an example of wireless communication in the case where a Local Network (LN) is adopted as the form of D2D communication. Referring to fig. 10, similar to fig. 9, various nodes are shown. In this example, the terminal device 100A, the terminal device 100B, and the terminal device 100C constitute an LN. In this LN, there is a master-slave relationship between the terminal apparatuses 100. In this example, the terminal device 100A is a master device, and the terminal device 100B and the terminal device 100C are slave devices. The master device (terminal device 100A) controls wireless communication in the LN. For example, the master device (terminal device 100A) functions as a base station masqueradingly (i.e., has a part of the functions of a base station). Furthermore, the master device (terminal device 100A) may function as a relay station that takes over wireless communication between the LN and the base station in order to realize a connection from the LN to a network (e.g., the internet). Note that solid arrows indicate transmission and reception of control information and data, and broken arrows indicate transmission and reception of control information. However, the transmission and reception of data may also be performed in the transmission and reception indicated by the dotted arrow.

Fig. 11 is an explanatory diagram illustrating an example of wireless communication in the case where the individual D2D communication is adopted as the form of D2D communication. Referring to FIG. 11, various nodes are shown, similar to FIG. 9. In this example, the terminal device 100A and the terminal device 100B perform D2D communication separately. In the example of fig. 11, unlike the example of fig. 10, LN is not formed, so that there is no master-slave relationship between the terminal device 100A and the terminal device 100B, or even if there is a master-slave relationship, the relationship is weaker. Note that solid arrows indicate transmission and reception of control information and data, and broken arrows indicate transmission and reception of control information. However, the transmission and reception of data may also be performed in the transmission and reception indicated by the dotted arrow.

First embodiment

A first embodiment of the present disclosure is described below with reference to fig. 12 to 32.

<3.1. Overview >

First, referring to fig. 12, a first embodiment is explained. In the first embodiment, as described with reference to fig. 10, as a form of D2D communication, a Local Network (LN) is employed. Subsequently, the master in the LN decides the size of data to be transmitted and received in the D2D communication. A specific example of this will be described below with reference to fig. 12.

Fig. 12 is an explanatory diagram illustrating an outline of the first embodiment. Referring to fig. 12, 3 terminal apparatuses 100 forming a Local Network (LN) are shown. In this example, the terminal device 100A is a master device in the LN, and the terminal device 100B and the terminal device 100C are slave terminals in the LN. In the first embodiment, thus, LN is adopted as the form of D2D communication. Subsequently, the master terminal (i.e., the terminal device 100A) decides the size of data to be transmitted and received in the D2D communication within the LN. For example, the size of data to be transmitted and received in D2D communication between the terminal device 100B and the terminal device 100C is decided by the terminal device 100A. Further, for another example, the size of data to be transmitted and received in the D2D communication between the terminal device 100A and the terminal device 100B is decided by the terminal device 100A.

<3.2. Functional Structure of terminal device >

Referring to fig. 13 to 16, an example of the functional structure of the terminal device 100-1 according to the first embodiment is explained. Fig. 13 is a block diagram illustrating an example of the functional structure of the terminal device 100-1 according to the first embodiment. Referring to fig. 13, the terminal device 100-1 includes an antenna unit 110, a wireless communication unit 120, a storage unit 130, an input unit 140, a display unit 150, and a processing unit 160.

(antenna element 110)

The antenna unit 110 receives a wireless signal and outputs the received signal to the wireless communication unit 120. Further, the antenna unit 110 transmits a transmission signal output by the wireless communication unit 120.

(Wireless communication Unit 120)

The wireless communication unit 120 performs wireless communication with another device. For example, when the terminal device 100-1 is placed in the cell 11, the wireless communication unit 120 performs wireless communication with the base station 10. Further, in particular, in the embodiment according to the present disclosure, the wireless communication unit 120 performs wireless communication with another terminal device 100.

(storage Unit 130)

The storage unit 130 holds programs and data for operating the terminal device 100-1.

For example, the storage unit 130 holds information about the size of data to be transmitted and received in wireless communication. More specifically, for example, the storage unit 130 holds a table of candidate TBSs as shown in fig. 5. Further, for example, the storage unit 130 holds a table of correspondence between MCS indexes and TBS indexes as shown in fig. 7 and 8. Further, the storage unit 130 holds a table of CQI as shown in fig. 6.

(input Unit 140)

The input unit 140 receives an input of a user of the terminal device. The input unit 140 supplies the input result to the processing unit 160.

(display Unit 150)

The display unit 150 displays an output screen (i.e., an output image) from the terminal device 100-1. For example, the display unit 150 displays an output image according to the control of the processing unit 160 (display control unit 169).

(processing unit 160)

The processing unit 160 provides various functions of the terminal device 100-1. The processing unit 160 includes a radio resource information acquisition unit 161, a data size decision unit 163, a notification unit 165, a communication control unit 167, and a display control unit 169.

(radio resource information acquiring unit 161)

The radio resource information acquisition unit 161 acquires information related to available radio resources.

Radio resources usable for wireless communication between a base station and a terminal device

For example, the radio resource information acquisition unit 161 acquires information on radio resources usable for radio communication between the base station 10 and the terminal device 100-1, among radio resources controllable by the base station 10. For example, the radio resources controllable by the base station 10 are radio resources that can be allocated by the base station 10. Specifically, for example, base station 10 reports information on downlink radio resources in the form of downlink allocation, and radio resource information acquisition section 161 acquires information on downlink radio resources via radio communication section 120. The base station 10 reports information on uplink radio resources in a form allowing uplink access, and the radio resource information acquisition unit 161 acquires information on uplink radio resources via the radio communication unit 120.

Radio resources (D2D resources) available for D2D communication

Acquisition of information relating to D2D resources

In particular, in the embodiment of the present disclosure, the radio resource information acquisition unit 161 acquires radio resource information on radio resources (hereinafter referred to as "D2D resources") available for D2D communication not via the base station 10 among radio resources controllable by the base station 10. As described above, the radio resources controllable by the base station 10 are, for example, radio resources that can be allocated by the base station 10. In particular, in the first embodiment, when the terminal device 100-1 is the master terminal in the LN, the radio resource information acquisition unit 161 acquires radio resource information related to D2D resources.

For example, the D2D resources are part or all of the radio resources reported by the base station 10 as available radio resources. In this way, when the base station 10 reports available radio resources, the occurrence of interference in D2D communication and/or interference caused by D2D communication can be suppressed.

For example, the D2D communication is wireless communication controlled by the terminal device 100-1 in the LN. In this case, the terminal device 100-1 allocates D2D resources as radio resources for D2D communication.

For example, when being the master in the LN, the terminal device 100-1 (for example, the radio resource information acquisition unit 161) notifies the base station 10 of available radio resources, and allocates radio resources for D2D communication in the LN from among the available radio resources. As a result, the allocated radio resource becomes a D2D resource (i.e., a radio resource available for D2D communication). The radio resource information acquisition unit 161 then acquires information related to the allocated radio resources (i.e., D2D resources).

As the available radio resources, the radio resources reported by the base station 10 are, for example, radio resources allocated to LNs. A specific example of radio resources available for D2D communication is described below with reference to fig. 14.

Fig. 14 is an explanatory diagram illustrating an example of D2D resources. Referring to fig. 13, the base station 10 first allocates a part of radio resources among radio resources controllable by the base station 10 to the LN. The base station 10 then informs the terminal device 100A of the radio resources on any channel (e.g., PDCCH, PDSCH or PBCH). The terminal device 100A (e.g., the radio resource information acquisition unit 161) then allocates a part or all of the radio resources allocated to the LN as radio resources (i.e., D2D resources) for D2D communication in the LN. For example, the terminal device 100A allocates a part of the radio resources allocated to the LN as radio resources for transmission from the terminal device 100B to the terminal device 100C. Further, the terminal device 100A allocates another part of the radio resources allocated to the LN as radio resources for transmission from the terminal device 100B to the terminal device 100A.

Such resource allocation can avoid the base station 10 from performing resource allocation for the individual D2D communication, thereby suppressing an increase in load on the base station 10.

For example, as described above, when the terminal device 100-1 is a master terminal in an LN, the radio resource information acquisition unit 161 allocates radio resources for D2D communication (i.e., D2D resources) and acquires radio resource information related to the radio resources.

Note that the radio resource information related to the D2D resources includes, for example, information identifying radio resources (e.g., resource blocks) available for D2D communication.

Resource allocation by means of a base station

For example, when the predetermined condition is satisfied, the base station 10 allocates radio resources to LNs. As a first example, the predetermined condition is to obtain a resource allocation request from the terminal device 100 (e.g., master device) included in the LN. Further, as a second example, when a service of performing D2D communication in LN at a predetermined timing is provided, the predetermined condition is that the predetermined timing is reached. Further, as a third example, the predetermined condition is that retransmission is required due to an error occurring in D2D communication in LN.

Resource allocation using terminal devices (master devices)

Further, for example, when the predetermined condition is satisfied, the terminal device 100-1 (master device) allocates a part or all of the radio resources (radio resources allocated to LN) reported by the base station 10 to the terminal device 100-1 as radio resources (i.e., D2D resources) for D2D communication in LN. For example, the predetermined condition is to obtain a resource allocation request from another terminal device 100-1 as a slave device. For example, the request includes an ID of the terminal device 100-1 on the other side of the D2D communication, a total amount of data, and an application type (e.g., qoS) of the data. Further, for another example, when a service of performing D2D communication in LN at a predetermined timing is provided, the predetermined condition is that the predetermined timing is reached. Further, for another example, the predetermined condition is that retransmission is required due to an error occurring in D2D communication in LN.

The number of radio resources to be allocated may be a number corresponding to the content of the request for D2D communication, or may be a predetermined number (e.g., 1 RB). Further, when the target communication is a retransmission of the preceding communication, the number of resources to be allocated may be decided in consideration of the status of the retransmission. When the target communication is retransmission of the preceding communication, the amount of resources to be allocated may be the amount that enables transmission of retransmission data, or may be as large as possible when it is difficult to transmit all of the retransmission data.

In addition, radio resources for transmission and reception of ACK/NACK may also be allocated along with radio resources for transmission and reception of data. The time interval between the radio resources for transmission and reception of data and the radio resources for transmission and reception of ACK/NACK may be a predetermined time interval or may be specified at any time. When the time interval is a predetermined time interval, notification of radio resources for transmission and reception of ACK/NACK is not required, resulting in reduction of overhead. The terminal device 100-1 as a master device may not allocate radio resources for transmission and reception of ACK/NACK for another wireless communication.

Another example of radio resources reported by a base station

Further, the example in which the radio resources allocated to the LN are reported by the base station 10 as the available radio resources was described above, but the embodiment according to the present disclosure is not limited to such an example. As a first example, the base station 10 may notify the terminal device 100-1 of radio resources allocated to the terminal device 100-1 (e.g., master device) in the form of available radio resources. In this case, the radio resource allocated to the terminal device 100-1 may be a radio resource allocated to the terminal device 100-1 as a radio resource for radio communication between the base station 10 and the terminal device 100-1. On the other hand, the radio resource allocated to the terminal device 100-1 may be a radio resource allocated to the terminal device 100-1 as a radio resource for D2D communication. Further, as a second example, the base station 10 may notify the terminal device 100-1 of unallocated radio resources in the form of available radio resources. In this case, the unallocated radio resource may be directly reported as a specific radio resource, or the unallocated radio resource may be indirectly reported as a radio resource other than the allocated radio resource. When indirectly reporting the unassigned radio resources, the terminal device 100-1 may confirm the radio resources assigned by the base station 10 (e.g., all radio resources used for radio communication between the base station 10 and any terminal device 100-1). The terminal device 100-1 then regards the radio resources other than the acknowledged radio resources as unallocated radio resources (i.e., available radio resources).

Note that the base station 10 includes a notification unit that notifies the terminal device 100 of available radio resources.

(data size determination section 163)

The data size determining unit 163 determines the size of data to be transmitted and received in D2D communication based on radio resource information related to D2D resources. In particular, in the first embodiment, when the terminal device 100-1 is the master device in the LN, the data size decision unit 163 decides the size.

-size to be determined

As a first example, the size to be determined is one of a plurality of predetermined sizes. Specifically, for example, the size to be decided is one of candidate TBSs as shown in fig. 5.

As a second example, the size to be decided is a size calculated from radio resources related to D2D resources.

-decisions based on modulation scheme and coding scheme

For example, data size determining section 163 determines the size according to at least one of the modulation scheme and the coding scheme. For example, data size determining section 163 determines the size based on radio resource information on D2D resources, and the modulation scheme and coding scheme.

-decision based on modulation scheme and coding scheme to be used in D2D communication

As a first example, the modulation scheme and the coding scheme are those to be used in D2D communication by a device performing D2D communication. In this way, when the size of data is decided according to the modulation scheme and/or coding scheme to be actually used, the size of data that can be transmitted can be calculated more accurately. Thus, a larger value can be determined as the size of the data.

Note that, for example, when the terminal device 100-1 is not a device performing D2D communication, the data size decision unit 163 obtains channel information related to a channel to be used in D2D communication, and identifies a modulation scheme and a coding scheme to be used in D2D communication from the information. The information related to the channel is, for example, channel State Information (CSI). The CSI includes CQI. The data size determining unit 163 then recognizes the modulation scheme and the coding scheme corresponding to the CQI. This enables identification of the modulation scheme and the coding scheme to be used even when the terminal device 100-1 is not a device performing D2D communication.

-decision based on predetermined modulation scheme and predetermined coding scheme

As a second example, when the terminal apparatus 100-1 is not an apparatus performing D2D communication, the modulation scheme and the coding scheme are a predetermined modulation scheme and a predetermined coding scheme. Such a decision based on the predetermined modulation scheme and the data size of the predetermined coding scheme does not require information about the channel to be used in D2D communication. Thus, it is not necessary to feed back channel-related information from the slave device to the master device. As a result, overhead can be reduced. Further, as another point of view, such a decision enables the size of data to be decided even when information related to a channel is not sufficiently obtained.

Further, for example, the predetermined modulation scheme is a modulation scheme having the lowest data rate among a plurality of available modulation schemes. The predetermined coding scheme is a coding scheme having the lowest data rate among a plurality of available coding schemes. This makes it possible to transmit and receive data more surely. For example, when the state of a channel to be used in D2D communication is poor, data can be correctly transmitted and received.

-a decision based on the number of radio resources

-a decision based on the number of resources for data

As a first example, the data size determining unit 163 calculates the number of data resources available for transmission and reception of data based on the radio resource information related to the D2D resources. The data size determining unit 163 determines the size based on the number of data resources and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

For example, the data size decision unit 163 calculates the number of Resource Elements (REs) available for transmission and reception of data in the D2D resource as the number of resources for data. For example, the data size decision unit 163 calculates the number of REs in the D2D resource except for REs for control signals (e.g., synchronization signals, reference signals, and signals of control channels). The data size decision unit 163 then decides the size according to the calculated number of resources for data (i.e., the number of REs), and the modulation scheme and coding scheme.

This enables the size of data that can be transferred to be calculated more accurately, thereby enabling a larger value to be decided as the size of the data.

Further, more specifically, for example, the data size decision unit 163 calculates the maximum value of the size of data to be transmitted, based on the calculated number of resources for data (i.e., the number of REs), and the modulation scheme and the coding scheme. The data size decision unit 163 then decides one of a plurality of predetermined sizes as the size of data to be transmitted and received in D2D communication, based on the calculated maximum value. For example, the plurality of predetermined sizes are candidate TBSs shown in fig. 5. The data size decision unit 163 then decides, as the size, a candidate equal to or smaller than the calculated maximum value among the candidate TBSs. For example, when the table shown in fig. 5 is provided, a column to be referred to in the table is decided according to the number of available radio resources (e.g., the number of RBs). Then, since the range of TBS index is decided according to the modulation scheme and the coding scheme, one or more rows to be referred to in the table are decided. Then, a candidate TBS equal to or smaller than the maximum value among some candidate TBSs corresponding to the one column and the one or more rows is first selected. Further, the largest candidate TBS among the selected candidate TBSs is finally selected. Thus, the largest candidate TBS among the candidate TBSs equal to or smaller than the calculated maximum value is selected. The final selected candidate TBS is determined as the size of the data to be transmitted and received in the D2D communication.

Note that instead of deciding any candidate in the candidate TBS as the size, the maximum value of the size of the data calculated from the calculated number of resources for data (i.e., the number of REs), and the modulation scheme and the coding scheme itself may be decided as the size of the data to be transmitted and received in the D2D communication, thereby enabling a larger value to be decided as the size of the data.

-decision based on the number of D2D resources

As a second example, data size determining section 163 determines, as the size, the smallest size among one or more predetermined sizes corresponding to at least one of the modulation scheme and the coding scheme, and the number of D2D resources, based on radio resource information related to D2D resources and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

For example, data size determining section 163 determines the smallest candidate TBS among candidate TBSs corresponding to the number of D2D resources, modulation scheme and coding scheme, as the size of data to be transmitted and received in D2D communication. As described above, for example, when the table shown in fig. 5 is provided, a column to be referred to in the table is decided according to the number of D2D resources (e.g., the number of RBs). Then, since the range of TBS index is decided according to the modulation scheme and the coding scheme, one or more rows to be referred to in the table are decided. Then, among some candidate TBSs corresponding to the one column and the one or more rows, the smallest candidate TBS is selected. The selected candidate TBS is then determined as the size of the data to be transmitted and received in the D2D communication.

This can avoid the terminal device 100-1 from calculating the number of resources for data available for transmission of data, thereby enabling the load of the terminal device 100-1 to be reduced.

As described above, the size of data to be transmitted and received in D2D communication is decided. This makes it possible to suppress an increase in the load of the base station 10 when D2D communication is performed.

More specifically, when the base station 10 decides the size of data to be transmitted and received in D2D communication, the base station 10 will collect various information related to D2D communication. As a result, overhead for information collection of the base station may be increased. In addition, a heavy load on the management and control of D2D communication may be imposed on the base station. However, as described above, when the terminal device 100, not the base station 10, decides the size of data, information collection, management, and control of the base station are reduced, thereby enabling suppression of an increase in load of the base station 10.

(notification Unit 165)

The notification unit 165 notifies the other device that assumes D2D communication of size-related information related to the decided size. In particular, in the first embodiment, when the terminal device is the master device in the LN, the notification unit 165 notifies the other device (slave device) of the size-related information.

-size related information

-information corresponding to a predetermined size

As a first example, the decided size is one of a plurality of predetermined sizes, and the size-related information is information corresponding to one of the plurality of predetermined sizes.

Specifically, for example, the decided size is one candidate among the candidate TBSs shown in fig. 5. Further, the size-related information is a TBS index or an MCS index.

This enables suppression of the number of radio resources required for notification, compared to when information indicating the size is notified. That is, overhead can be suppressed.

-information indicating size

As a second example, the size-related information is information indicating the decided size.

Specifically, as described above, for example, the decided size is a size calculated from radio resource information related to D2D resources. The calculated size is then determined as the size of the data to be transmitted and received in the D2D communication. In this case, the size-related information is a calculated and decided size.

This enables a larger size to be notified than in the case of transmitting information (e.g., index) corresponding to a predetermined size, thus improving throughput in D2D communication.

-the channel used

-control channel

As a first example, the size-related information is notified to another device by transmission on a control channel for transmitting a control signal.

Specifically, for example, in D2D communication, a channel similar to that in wireless communication between the base station 10 and the terminal device 100-1 may also be used. For example, in D2D communication, a control channel corresponding to PDCCH and a data channel corresponding to PDSCH are also used. In this case, the size-related information is notified to another device through transmission on a control channel corresponding to the PDCCH. A specific example of this will be described below with reference to fig. 15.

Fig. 15 is an explanatory diagram illustrating an example of the above control channel transmitting the size-related information. Referring to fig. 15, a radio resource including a control channel corresponding to a PDCCH and a data channel corresponding to a PDSCH is shown. As shown in fig. 15, size-related information is transmitted on a control channel corresponding to the PDCCH.

The use of the control channel in this manner enables the decided size to be notified or informed also in D2D communication as in the case of wireless communication between the base station 10 and the terminal device 100-1.

-data channel

As a second example, the size-related information is notified to another device by transmission over a data channel for transmitting data.

Specifically, for example, in D2D communication, a channel similar to that in wireless communication between the base station 10 and the terminal device 100-1 may also be used. For example, in D2D communication, a data channel corresponding to PDCCH (control channel corresponding to PDCCH), and a data channel corresponding to PDSCH are also used. In this case, the size-related information is notified to another device through transmission on a control channel corresponding to the PDCCH. A specific example of this will be described below with reference to fig. 16.

Fig. 16 is an explanatory diagram illustrating an example of the above data channel transmitting size-related information. Referring to fig. 15, a radio resource including a control channel corresponding to a PDCCH and a data channel corresponding to a PDSCH is shown. As shown in fig. 15, the size-related information is transmitted not only on a control channel corresponding to the PDCCH but also on a data channel corresponding to the PDSCH. Note that from the viewpoint of decoding order, it is preferable to use radio resources faster in the time direction in the data channel.

The use of the data channel in this way enables the determined size to be informed even when the information cannot be successfully transmitted on the control channel.

As described above, the device performing D2D communication is notified of the size-related information, thereby making it possible to use the decided size in D2D communication.

Notification of D2D resources

Note that, among the devices performing D2D communication, another device is notified not only of size-related information but also of D2D resources. For example, the D2D resource is notified to a transmission side device in D2D communication as a transmission resource, and the D2D resource is notified to a reception side device in D2D communication as a reception resource.

For example, the notification unit 165 notifies the D2D resource together with the size-related information to another device. The notification unit 165 then notifies the transmission-side device of the radio resource as a transmission resource, and notifies the reception-side device of the radio resource as a reception resource. The radio resource is notified to another device by transmission on a control channel and/or a data channel.

Such notification allows for proper transmission and reception in D2D communications.

(communication control unit 167)

Communication control unit 167 controls wireless communication of terminal device 100-1. For example, when the terminal device 100-1 performs wireless communication with the base station 10, the communication control unit 167 controls wireless communication of the terminal device 100-1 with the base station 10.

In particular, in an embodiment according to the present disclosure, the communication control unit 167 controls D2D communication of the terminal device 100-1. Specifically, when the terminal device 100-1 performs D2D communication, the communication control unit 167 transmits or receives data having the decided data size using a radio resource (D2D resource) available for D2D communication.

Note that in the first embodiment, when the terminal device 100-1 is a slave device in the LN, the master device notifies the terminal device of size-related information. For example, the size-related information is information corresponding to one of a plurality of predetermined sizes. Specifically, the size-related information is a TBS index or an MCS index. In this case, for example, the communication control unit 167 identifies a TBS corresponding to the TBS index and the number of D2D resources (the number of RBs) as the size of data to be transmitted and received in D2D communication, using a table of candidate TBSs or the like as shown in fig. 5. Further, for another example, the size-related information is information indicating the size. In this case, the communication control unit 167 recognizes the size indicated by the size-related information as the size of data to be transmitted and received in the D2D communication.

(display control unit 169)

The display control unit 169 controls display of an output screen by the display unit 150. For example, the display control unit 169 generates an output screen to be displayed by the display unit 150 to allow the display unit 150 to display the output screen.

<3.3. Flow of treatment >

An example of the communication control process according to the first embodiment is described below with reference to fig. 17 to 23.

(entire flow of communication control processing)

Referring first to fig. 17 and 18, a schematic flow of the communication control process according to the first embodiment is explained.

Cases of D2D communication between slave devices

Fig. 17 is a sequence chart illustrating a first example of a schematic flow of the communication control process according to the first embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The terminal device 100 estimates the state of the channel available for D2D communication. For example, the terminal device 100 estimates the state of the channel by receiving a reference signal transmitted by another terminal device 100. The terminal device 100B and/or the terminal device 100C as the slave device in the LN then feeds back the information on the channel to the terminal device 100A as the master device in the LN (S310). The information related to the channel is Channel State Information (CSI), including CQI, RI, PMI, RSRP, RSRQ, etc. Note that the information related to the channel may also be fed back to the base station 10 via the master device, or directly from the slave device.

Further, when the predetermined condition is satisfied, the base station 10 allocates a part of radio resources among radio resources controllable by the base station 10 to the LN (S320). Note that when information related to a channel is also fed back to the base station 10, the base station 10 may allocate radio resources in consideration of the information.

The base station 10 then notifies the terminal device 100A as the master of the radio resources allocated to the LN on an arbitrary channel (for example, PDCCH, PDSCH, or PBCH) (S330).

After that, the terminal device 100A (radio resource information acquisition unit 161) as the master allocates radio resources for D2D communication in the LN from among the radio resources allocated to the LN (S340). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication.

The terminal device 100A (data size decision unit 163) then decides the size of data to be transmitted and received in D2D communication (S400). The flow of this process is described in detail later.

After that, the terminal device 100A (notification unit 165) notifies the D2D resource and the size-related information related to the decided size to another device (slave device) performing D2D communication (S350).

The terminal device 100B and the terminal device 100C then transmit and receive data having the decided size using the D2D resource (S360).

Case of D2D communication between master device and slave device

Fig. 18 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the first embodiment. In this case, the terminal device 100A as the master device and the terminal device 100B as the slave device perform D2D communication.

In addition, in the example shown in fig. 18, steps S310 to S350 are included similarly to the example shown in fig. 17. Then, finally, the terminal apparatus 100A as a master and the terminal apparatus 100B as a slave transmit and receive data having a predetermined size using D2D (S361).

(flow of processing related to determination of data size)

An example of a process of deciding the size of data to be transmitted and received in D2D communication is described below with reference to fig. 19 to 23.

First example

In step S410, the data size decision unit 163 calculates the number of data resources (e.g., the number of REs) available for transmission and reception of data in the D2D resources based on the radio resource information related to the D2D resources (radio resources available for D2D communication).

In step S420, the data size determining unit 163 obtains information of the modulation scheme and the coding scheme to be used in the D2D communication.

In step S430, the data size determining unit 163 calculates the maximum value of the size of data to be transmitted in D2D communication based on the calculated amount of data resources, and the modulation scheme and the coding scheme (S430).

In step S440, the data size decision unit 163 decides one of a plurality of predetermined sizes (for example, candidate TBSs) as the size of data to be transmitted and received in D2D communication, based on the calculated maximum value. The process then ends.

Thus, according to the first example, a larger value can be determined as the size of the data.

Second example

The difference between the first example shown in fig. 19 and the example of the second modification shown in fig. 20 is that steps S421 and S423 are not included in the first example, but steps S421 and S423 are included in the second example. Thus, only steps S421 and S423 are described here.

In step S421, the data size determining unit 163 determines whether or not the D2D communication using the radio resource that is the object of the size determination is the primary communication. If the D2D communication is the primary communication, the process advances to step S423. Otherwise, the process advances to step S420.

In step S423, the data size determining unit 163 obtains information on a predetermined modulation scheme and a predetermined coding scheme. The predetermined modulation scheme is a modulation scheme having the lowest data rate among a plurality of available modulation schemes. The predetermined coding scheme is one of a plurality of available coding schemes, and has the lowest data rate.

Thus, according to the second example, even when the information related to the channel is insufficient when the size of the data for the primary communication is decided, the data in the primary communication can be transmitted and received more surely.

Third example

The difference between the first example shown in fig. 19 and the third example shown in fig. 21 is that in the first example, step S420 is included, but in the third example, step S423 is included instead of step S420. Then, only step S423 will be described here.

Thus, according to the third example, since the size is decided according to the predetermined modulation scheme and the predetermined coding scheme, unlike step S310 in fig. 17, it is not necessary to feed back information on the channel from the slave device to the master device, thereby making it possible to suppress overhead.

Fourth example

The difference between the first example shown in fig. 19 and the fourth example shown in fig. 22 is that in the first example, steps S420, S430, and S440 are included, and in the fourth example, step S441 is included instead of these steps. Thus, only step S441 is described here.

In step S441, the data size determining unit 163 determines the smallest size among one or more predetermined sizes corresponding to the number of D2D resources (for example, the number of PB) and the modulation scheme and the coding scheme as the size of data to be transmitted and received in D2D communication. The process then ends.

Thus, according to the fourth example, the terminal device 100 may not count the number of resources for data available for transmission of data, thereby enabling suppression of the load on the terminal device 100.

-fifth example

The difference between the first example shown in fig. 19 and the fifth example shown in fig. 23 is that in the first example, step S440 is included, and in the fifth example, step S443 is included instead of step S440. Then, only step S443 is described here.

In step S443, the data size decision unit 163 decides the calculated maximum value as the size of data to be transmitted and received in the D2D communication. The process then ends.

Thus, according to the fifth example, a larger value can be determined as the size of the data.

The first example of the process of determining the size of data to be transmitted and received in D2D communication was described above, and as a modification of the first example, the second to fifth examples are described. Note that two or more of the four modifications may be combined. For example, in the fourth example shown in fig. 22, step S420 may be replaced with step S423 in the third example shown in fig. 21.

<3.4. First modification example >

Next, a first modification of the first embodiment will be described with reference to fig. 24 and 25.

In a first embodiment, a master in the LN decides the size of data to be transmitted and received in D2D communication. Thus, in the case of D2D communication between slave devices in the LN, the master device does not directly engage in the D2D communication, but decides the size of data to be transmitted and received in the D2D communication. Thus, in the first embodiment described above, the master device will decide the size of data to be transmitted and received in D2D communication without knowing whether there is retransmission for D2D communication between the slave devices (i.e., ACK/NACK for D2D communication between the slave devices). That is, the master device cannot decide the size of data in consideration of retransmission in D2D communication between the slave devices. On the other hand, when hybrid automatic repeat request (HARQ) is used, in the case of retransmission, it is required that the size of data should be the same as the size of data transmitted last time.

Then, according to a first modification of the first embodiment, the slave device determines the size of the data in consideration of retransmission in D2D communication between the slave devices.

(communication control unit 167)

In particular, in the first modification of the first embodiment, when the terminal device 100-1 is a slave device in the LN, the communication control unit 167 controls transmission of data in consideration of whether or not the target transmission is retransmission.

(flow of processing)

Communication control processing according to a first modification of the first embodiment

Fig. 24 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the first embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in LN, perform D2D communication.

The difference between the first example according to the first embodiment shown in fig. 17 and the example according to the first modification of the first embodiment shown in fig. 24 is that in the first example according to the first embodiment, step S360 is included, but in the example according to the first modification of the first embodiment, steps S370 and S363 are included instead of step S360. Thus, only steps S370 and S363 are described here.

The terminal device 100B and the terminal device 100C as slave devices determine the size of data according to whether or not the target transmission is retransmission (S370). The flow of this process is described in detail later.

The terminal device 100B and the terminal device 100C then transmit and receive data having the determined size using the D2D resource (S363).

Flow of processing related to determination of data size

Fig. 25 is a flowchart illustrating an example of a schematic flow of a process of determining the size of data to be transmitted and received in D2D communication. The process is a process in the slave device.

In step S371, the communication control unit 167 of the terminal device 100 as the slave device determines whether the target transmission (i.e., the D2D communication between the slave devices) is retransmission. If the target transmission is retransmission, the process advances to step S373. Otherwise, the process advances to step S377.

In step S373, the communication control unit 167 determines whether the size of the retransmission data (or the remaining data after division) exceeds the size of the master report (i.e., the size corresponding to the size-related information). When the size of the retransmission data exceeds the size of the report, the process advances to step S375. Otherwise, the process advances to step S379.

In step S375, the communication control unit 167 divides the reported size (or the divided remaining data) into data having the reported size and data having the remaining size.

In step S377, the communication control unit 167 decides the size of the report as the size of data to be transmitted and received in the D2D communication. The process then ends.

In step S379, the communication control unit 167 decides the size of the retransmission data (or the divided remaining data) as the size of the data to be transmitted and received in the D2D communication. The process then ends.

Note that when data is divided and transmitted, the divided data is synthesized and decoded.

The first modification of the first embodiment is explained above. According to the first modification of the first embodiment, even when a terminal device not directly involved in D2D communication decides the size of data, data having a size in consideration of retransmission is transmitted and received in D2D communication.

<3.5. Second modification example >

Next, a second modification of the first embodiment will be described with reference to fig. 26 to 28.

According to the second modification of the first embodiment, the slave device feeds back information (e.g., ACK/NACK) on retransmission for D2D communication between the slave devices to the master device, and the master device performs resource control and data size determination in consideration of the presence or absence of retransmission.

(communication control unit 167)

In particular, in the second modification of the first embodiment, when the terminal device 100-1 is a slave device in the LN, the communication control unit 167 feeds back information on retransmission for D2D communication between the slave devices to the master device through the wireless communication unit 120. For example, ACK/NACK for D2D communication between the slave devices is fed back to the master device as information related to retransmission. Note that, for example, the radio resources for the feedback may be allocated by the master in the LN.

(radio resource information acquiring unit 161)

As described above, the terminal device 100-1 (for example, the radio resource information acquisition unit 161) allocates radio resources for D2D communication in the LN from among radio resources reported by the base station 10 as available radio resources. The allocated radio resource becomes a D2D resource (radio resource for D2D communication). In the first embodiment, the terminal device 100-1 performs such resource allocation when it is the master in the LN.

In particular, in the second modification of the first embodiment, the terminal device 100-1 (e.g., the radio resource information acquisition unit 161) considers whether or not the D2D communication (i.e., the target transmission) between the slave devices is retransmission to allocate radio resources for the D2D communication between the slave devices. For example, when the target transmission is a retransmission, radio resources are preferentially allocated for the transmission from the point of view of time and/or the amount of resources.

Note that, even in D2D communication between the master device and the slave device, wireless resources for D2D communication may be allocated in consideration of whether the D2D communication is retransmission.

(data size determination section 163)

As described above, the data size decision unit 163 decides the size of data to be transmitted and received in D2D communication. In the first embodiment, the terminal device 100-1 decides the size in this way when it is the master in the LN.

In particular, in the second modification of the first embodiment, the data size decision unit 163 considers whether the D2D communication (i.e., the target transmission) between the slave devices is retransmission or not to decide the size of data to be transmitted and received in the D2D communication between the slave devices. For example, when the target transmission is retransmission, the size of data to be transmitted and received is decided in consideration of the size of retransmission data.

(flow of processing)

Communication control processing according to the second modification of the first embodiment

Fig. 26 is a sequence diagram illustrating an example of a schematic flow of the communication control process according to the second modification of the first embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The difference between the first example according to the first embodiment shown in fig. 17 and the example according to the second modification of the first embodiment shown in fig. 26 is that in the first example according to the first embodiment, steps S340 and S400 are included, whereas in the example according to the second modification of the first embodiment, steps S381, S510 and S320 are included instead of steps S340 and S400. Thus, only steps S381, S510, and S520 are explained here.

After transmission and reception of data in D2D communication (S360), ACK/NACK is fed back between the terminal device 100B and the terminal device 100C performing D2D communication. Further, ACK/NACK is fed back from the terminal apparatus 100B and/or the terminal apparatus 100C to the terminal apparatus 100A as the master terminal (S381).

Further, the terminal device 100A (radio resource information acquisition unit 161) as the master terminal considers whether or not the D2D communication (i.e., target transmission) between the terminal device 100B and the terminal device 100C as the slave devices is retransmission to allocate radio resources for the D2D communication (S510). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication. The flow of this process is described in detail later.

Further, the terminal device 100A (data size deciding unit 163) as the master terminal considers whether or not the D2D communication (i.e., target transmission) between the terminal device 100B and the terminal device 100C as the slave devices is retransmission, to decide the size of data to be transmitted and received in the D2D communication (S520). The flow of this process is described in detail later.

Procedure of a process related to allocation of radio resources for D2D communication

In step S511, the radio resource information acquisition unit 161 of the terminal device 100 as the slave device determines whether the target transmission (i.e., the D2D communication between the slave devices) is retransmission. If the target transmission is retransmission, the process advances to step S511. Otherwise, the process advances to step S518.

In step S512, the radio resource information acquisition unit 161 determines whether or not the earlier radio resource in the time direction can be allocated. If the radio resources can be allocated, the process advances to step S513. Otherwise, the process advances to step S516.

In step S513, the radio resource information acquisition unit 161 determines whether or not radio resources required for transmission and reception of retransmission data (or remaining data after division) can be allocated. If the radio resources can be allocated, the process advances to step S514. Otherwise, the process advances to step S515.

In step S514, the radio resource information acquisition unit 161 allocates an earlier radio resource in the time direction required for transmission and reception of retransmission data (or remaining data after division) as a radio resource for D2D communication between the slave devices. The process then ends.

In step S515, the radio resource information acquisition unit 161 allocates an earlier radio resource in the time direction as a radio resource for D2D communication between the slave devices. The process then ends.

In step S516, the radio resource information acquisition unit 161 determines whether or not radio resources required for transmission and reception of retransmission data (or remaining data after division) can be allocated. If the radio resources can be allocated, the process advances to step S517. Otherwise, the process advances to step S518.

In step S517, the radio resource information acquisition unit 161 allocates radio resources required for transmission and reception of retransmission data (or remaining data after division) as radio resources for D2D communication between the slave devices. The process then ends.

In step S518, the radio resource information acquisition unit 161 allocates radio resources for D2D communication between the slave devices as usual. The process then ends.

As described above, the radio resources for D2D communication between the slave devices are allocated, and the allocated radio resources become radio resources (D2D resources) usable for D2D communication.

Flow of processing related to the decision of the size of the data

Fig. 28 is a flowchart illustrating an example of a schematic flow of processing of deciding the size of data to be transmitted and received in D2D communication between slave devices in the second modification of the first embodiment.

In step S521, the data size deciding unit 163 of the terminal device 100 as the master determines whether the target transmission (i.e., the D2D communication between the slave devices) is retransmission. If the target transmission is retransmission, the process advances to step S523. Otherwise, the process advances to step S400.

In step S523, the data size determining unit 163 determines whether or not the retransmission data (or the remaining data after segmentation) can be transmitted using the D2D resource. If the retransmission data (or the remaining data after the segmentation) can be transmitted, the process advances to step S525. Otherwise, the process advances to step S400.

In step S400, the data size decision unit 163 decides the size of data to be transmitted and received in D2D communication as usual. The process then ends. Note that when it is impossible to transmit retransmission data (or remaining data after segmentation) using D2D resources, the data is appropriately segmented in the slave device.

In step S525, the data size determining unit 163 determines the size of the retransmission data (or the remaining data after division) as the size of the data to be transmitted and received in the D2D communication. The process then ends.

The second modification of the first embodiment is explained above. According to the second modification of the first embodiment, even when a terminal device that is not involved in D2D communication directly decides the size of data, data having a size that is considered for retransmission is transmitted and received in D2D communication using a radio resource that is considered for retransmission. As a result, the efficiency of use of radio resources can be improved.

Note that ACK/NACK for D2D communication between the slave devices may be fed back not only to the master device but also to the base station 10. Such feedback may be done on a channel such as PUSCH or PUCCH. When feedback to the base station 10 is present, the base station 10 may perform resource control in consideration of the presence or absence of retransmission (ACK/NACK) for D2D communication between the slave devices. For example, when there is retransmission, radio resources are preferentially allocated to the LN (or master) from the viewpoint of time and/or the number of radio resources, thereby allowing notification of available radio resources by the base station in view of retransmission. As a result, the efficiency of use of radio resources can be improved.

<3.6. Third modification example >

Next, a third modification of the first embodiment will be described with reference to fig. 29.

In the example of the first embodiment described above, the terminal device 100-1 as the master allocates radio resources for D2D communication in LN from among radio resources reported by the base station 10 as available radio resources.

On the other hand, in particular, in the third modification of the first embodiment, the base station 10 directly allocates radio resources for D2D communication in LN.

(radio resource information acquiring unit 161)

In particular, in the third modification of the first embodiment, radio resources (D2D resources) available for D2D communication are allocated by the base station 10 as radio resources for D2D communication, and reported by the base station 10. That is, the base station 10 directly allocates radio resources for D2D communication in LN. The allocated radio resource becomes a D2D resource (radio resource usable for D2D communication). The terminal device 100-1 (e.g., the terminal device 100-1 as a master) is informed of the D2D resource.

Then, in particular, in the third modification of the first embodiment, when the terminal device 100-1 is the master device, the radio resource information acquisition unit 161 acquires information related to D2D resources to be reported to the base station 10.

(flow of processing)

Communication control processing according to a third modification of the first embodiment

Fig. 29 is a sequence diagram illustrating an example of a schematic flow of the communication control process according to the third modification of the first embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The difference between the first example according to the first embodiment shown in fig. 17 and the example according to the third modification of the first embodiment shown in fig. 29 is that in the first example according to the first embodiment, steps S320, S330, and S340 are included, whereas in the example according to the third modification of the first embodiment, steps S321 and S331 are included instead of these steps. Thus, only steps S321 and S331 are described here.

When the predetermined condition is satisfied, the base station 10 allocates a part of radio resources among radio resources controllable by the base station 10 as resources for D2D communication (S321). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication.

The base station 10 then notifies the terminal device 100A as a master of D2D resources on an arbitrary channel (e.g., PDCCH, PDSCH, or PBCH) (S331).

Note that the base station 10 may notify the terminal device 100B and the terminal device 100C as slave devices of the D2D resource.

The third modification of the first embodiment is explained above. According to the third modification of the first embodiment, the terminal device 100-1 may not perform resource control, thus enabling a reduction in load on the terminal device 100-1.

Note that the third modification of the first embodiment may be combined with one of the first modification and the second modification of the first embodiment. That is, even in the third modification of the first embodiment, step S370 and step S361 shown in fig. 24 may be performed instead of step S360 shown in fig. 29. Further, even in the third modification of the first embodiment, steps S381, S510, and S520 shown in fig. 26 may be performed instead of steps S340 and S400 shown in fig. 29.

<3.7. Fourth modification example >

Next, a fourth modification of the first embodiment will be described with reference to fig. 30 and 31.

In the example of the first embodiment described above, the base station 10 notifies the terminal device 100-1 of available radio resources (for example, radio resources allocated to LN, radio resources allocated to the terminal device 100-1, radio resources not allocated, and the like). The terminal device 100-1 as the master then allocates radio resources for D2D communication in LN from among radio resources reported from the base station 10.

On the other hand, in particular, in the fourth modification of the first modification, the available radio resources are not reported by the base station 10 but estimated by the terminal device 100-1.

(radio resource information acquiring unit 161)

In particular, in the fourth modification, the radio resources (D2D resources) available for D2D communication are part or all of the radio resources estimated as available radio resources. For example, the radio resource information acquisition unit 161 estimates available radio resources to allocate a part or all of the radio resources as radio resources for D2D communication. The allocated radio resource becomes a D2D resource.

Examples of estimated radio resources

For example, radio resources estimated not to be used by the base station are estimated as available radio resources. Specifically, the received power in the target radio resource (e.g., frequency band, time period, or a combination thereof) is measured, and based on the measurement result, it is determined whether the target radio resource is used by the base station. As a result, when it is determined that the radio resource is not used by the base station, it is estimated that the radio resource will not be used by the base station.

Note that, for another example, radio resources that are estimated to be used but do not interfere with wireless communication may be estimated as available radio resources. In this case, an interference control function (control of transmission power, etc.) included in the terminal device may be used.

-terminal equipment for performing the estimation

As a first example, the master in the LN estimates the available radio resources. That is, when the terminal device 100-1 is the master in the LN, the radio resource information acquisition unit 161 estimates the available radio resources. This eliminates the need to transmit and receive the estimation result in the LN, thereby making it possible to suppress overhead.

As a second example, two or more terminal devices in the LN estimate the available radio resources. For example, all the master and slave devices in the LN estimate available radio resources and share them. For example, radio resources estimated by all devices as available radio resources may become D2D resources. This increases the likelihood that the D2D resources are available radio resources. As another example, a radio resource estimated by at least one device as an available radio resource may be a D2D resource. This allows more D2D resources to be obtained.

(flow of processing)

Communication control process according to the fourth modification of the first embodiment (case where the master performs estimation)

Fig. 30 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to a fourth modification of the first embodiment. In this example, the master device estimates available radio resources.

The difference between the first example according to the first embodiment shown in fig. 17 and the example according to the fourth modification of the first embodiment shown in fig. 30 is that in the first example according to the first embodiment, steps S320 and S330 are included, and in the first example according to the fourth modification of the first embodiment, step S323 is included instead of these steps. Then, step S323 is described here.

The terminal device 100A (radio resource information acquisition unit 161) as the master device estimates the available radio resources (S323). The estimated radio resources become radio resources (D2D resources) available for D2D communication.

Communication control processing according to the fourth modification of the first embodiment (case where two or more devices make estimation)

Fig. 31 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the fourth modification of the first embodiment. In this example, the available radio resources are estimated and shared by the master device and the slave device.

The difference between the first example according to the fourth modification of the first embodiment shown in fig. 30 and the second example according to the fourth modification of the first embodiment shown in fig. 31 is that in the first example, step S323 is included, and in the second example, step S325 is included instead of step S323. Then, step S325 is described here.

The terminal device 100A as a master device, and the terminal device 100B and the terminal device 100C as slave devices estimate available radio resources and share the available radio resources (S325).

The fourth modification of the first embodiment is explained above. According to the fourth modification of the first embodiment, the base station 10 may not perform resource control for D2D communication. Thus, even when D2D communication is performed, the load on the base station 10 can be suppressed.

Second embodiment

A second embodiment of the present disclosure is described below with reference to fig. 32 to 40.

<4.1. Overview >

Referring first to fig. 32, a second embodiment is explained. In the second embodiment, as described with reference to fig. 10, as a form of D2D communication, a Local Network (LN) is employed. The size of the data to be transmitted and received in the D2D communication is then decided by the device (master device or slave device) performing the D2D communication. A specific example of this will be described below with reference to fig. 32.

Fig. 32 is an explanatory diagram illustrating an outline of the second embodiment. Referring to fig. 32, 3 terminal apparatuses 100 constituting a Local Network (LN) are shown. In this example, the terminal device 100A is a master device in the LN, and the terminal device 100B and the terminal device 100C are slave terminals in the LN. In the second embodiment, as such, LN is adopted as a form of D2D communication. Subsequently, at least one of the devices performing D2D communication within the LN decides on the size of data to be transmitted and received in the D2D communication. For example, the size of data to be transmitted and received in D2D communication between the terminal device 100B as a slave device and the terminal device 100C as a slave device is decided by the terminal device 100B or the terminal device 100C. Further, for another example, the size of data to be transmitted and received in D2D communication between the terminal device 100A as a master device and the terminal device 100B as a slave device is decided by the terminal device 100A or the terminal device 100B.

Note that in the first embodiment, the master decides the size of data to be transmitted and received in D2D communication, but in the second embodiment, the device performing D2D communication decides the size of data to be transmitted and received in D2D communication, regardless of whether it is the master or the slave.

<4.2. Functional Structure of terminal device >

Referring to fig. 33, an example of the functional structure of the terminal device 100-2 according to the second embodiment is explained. Fig. 33 is a block diagram illustrating an example of the functional structure of the terminal device 100-2 according to the second embodiment. Referring to fig. 33, the terminal device 100-2 includes an antenna unit 110, a wireless communication unit 120, a storage unit 130, an input unit 140, a display unit 150, and a processing unit 170.

Here, there is no difference between the first embodiment and the second embodiment in terms of the antenna unit 110, the wireless communication unit 120, the storage unit 130, the input unit 140, the display unit 150, and the display control unit 169 included in the processing unit 170. Thus, here, the radio resource information acquisition unit 171, the data size determination unit 173, the notification unit 175, and the communication control unit 177 included in the processing unit 170 are explained.

(radio resource information acquisition unit 171)

The radio resource information acquisition unit 171 acquires information on available radio resources.

For example, the radio resource information acquisition unit 171 acquires information on radio resources usable for radio communication between the base station 10 and the terminal device 100-2, among radio resources controllable by the base station 10. The content of this point is the same as that described in the first embodiment.

Radio resources (D2D resources) available for D2D communication

In particular, in the embodiment according to the present disclosure, the radio resource information acquisition unit 171 acquires radio resource information related to radio resources (D2D resources) available for D2D communication not through the base station 10. As described above, the radio resources controllable by the base station 10 are, for example, radio resources that can be allocated by the base station 10.

In the second embodiment, when the terminal device 100-2 is the master device, the radio resource information acquisition unit 171 acquires radio resource information related to D2D resources, similar to the radio resource information acquisition unit 161 in the first embodiment. On the other hand, when the terminal device 100-2 is a slave device, the terminal device 100-2 notifies the D2D resource by the master device. The radio resource information acquisition unit 171 then acquires radio resource information related to D2D resources reported by the master device.

(data size determination section 173)

The data size determining unit 173 determines the size of data to be transmitted and received in D2D communication based on radio resource information related to D2D resources.

In particular, in the second embodiment, the data size decision unit 173 decides the size when the terminal apparatus 100-2 performs D2D communication. Note that, when another device performing D2D communication decides the size and notifies the terminal device 100-2 of the size, the data size decision unit 173 may not decide the size. For example, when the terminal device 100-2 is a device on the transmission side in D2D communication, the data size determining unit 173 may determine the size, whereas when the terminal device 100-2 is a device on the reception side in D2D communication, the data size determining unit 173 may not determine the size. Further, for another example, in the case of D2D communication between the master device and the slave device, the data size determining unit 173 may determine the size when the terminal device 100-2 is the master device, and the data size determining unit 173 may not determine the size when the terminal device 100-2 is the slave device.

Note that the specific method of determining the size is similar to that described in the first embodiment.

(notification Unit 175)

The notification unit 175 notifies the other device performing D2D communication of size-related information related to the determined size. In particular, in the second embodiment, when the terminal device 100-2 performs D2D communication and decides the size, the notification unit 175 notifies the other device performing D2D communication of the size-related information.

Note that the specific content of the size-related information to be reported, and the specific notification method are similar to those described in the first embodiment.

Further, for example, when the terminal device 100-2 is a master device, the notification unit 175 notifies the D2D resource of a device performing D2D communication. The notification unit 175 then notifies the transmission-side device of the radio resource as the transmission resource, and notifies the reception-side device of the radio resource as the reception resource. The radio resource is notified to another device by transmission on a control channel and/or a data channel.

(communication control Unit 177)

The communication control unit 177 controls wireless communication of the terminal device 100-2. For example, when the terminal device 100-2 performs wireless communication with the base station 10, the communication control unit 177 controls wireless communication of the terminal device 100-2 with the base station 10.

In particular, in an embodiment according to the present disclosure, the communication control unit 177 controls D2D communication of the terminal device 100-2. Specifically, when the terminal device 100-2 performs D2D communication, the communication control unit 177 transmits or receives data having the decided data size using a radio resource (D2D resource) available for D2D communication.

Note that in the second embodiment, when D2D communication is performed, but the size of data to be transmitted and received in the D2D communication is not decided, the terminal device 100-2 notifies size-related information by another device performing D2D communication. In this case, the terminal device 100-2 can recognize the size of data to be transmitted and received in D2D communication using a method similar to that described in the first embodiment.

<4.3. Flow of treatment >

An example of the communication control process according to the second embodiment is described below with reference to fig. 34 and 35.

(general flow of communication control processing)

Referring first to fig. 34 and 35, a schematic flow of the communication control process according to the second embodiment is explained.

Cases of D2D communication between slave devices

Fig. 34 is a sequence chart illustrating a first example of a schematic flow of the communication control process according to the second embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The terminal device 100 estimates the state of the channel available for D2D communication. For example, the terminal device 100 estimates the state of the channel by receiving a reference signal transmitted by another terminal device 100. Subsequently, for example, information related to the channel is fed back between the terminal apparatuses 100 performing D2D communication (S610). The information related to the channel is Channel State Information (CSI), including CQI, RI, PMI, RSRP, RSRQ, etc. Note that channel related information may also be fed back to the master device and/or base station 10.

Further, when the predetermined condition is satisfied, the base station 10 allocates a part of radio resources among radio resources controllable by the base station 10 to the LN (S620). Note that when information related to a channel is also fed back to the base station 10, the base station 10 may allocate radio resources in consideration of the information.

The base station 10 then notifies the terminal device 100A as the master of the radio resources allocated to the LN on an arbitrary channel (for example, PDCCH, PDSCH, or PBCH) (S630).

After that, the terminal device 100A (radio resource information acquisition unit 171) as the master allocates radio resources for D2D communication in the LN from among the radio resources allocated to the LN (S640). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication. Note that when information related to a channel is also fed back to the terminal device 100A as a master device, the terminal device 100A may allocate radio resources in consideration of the information.

The terminal device 100A (notification unit 175) then notifies the devices (terminal device 100B and terminal device 100C) performing D2D communication of the D2D resource (S650).

Subsequently, the terminal device 100B (data size deciding unit 173), which is one of the devices performing D2D communication, decides the size of data to be transmitted and received in D2D communication (S700). The flow of this process is described later.

Subsequently, the terminal device 100B (notification unit 175) notifies the other device (terminal device 100C) performing D2D communication of size-related information related to the decided size (S660). Note that D2D resources may be reported together with size related information.

After that, the terminal device 100B and the terminal device 100C transmit and receive data having the decided size using the D2D resource (S670).

Case of D2D communication between master device and slave device

Fig. 35 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the second embodiment. In this case, the terminal device 100A as the master device and the terminal device 100B as the slave device perform D2D communication.

The first example shown in fig. 34 is similar to the second example shown in fig. 35, except whether the master device is included in the device that performs D2D communication.

(flow of processing related to determination of size of data)

In the second embodiment, as an example of processing for determining the size of data to be transmitted and received in D2D communication, the first example (fig. 19), the second example (fig. 20), the fourth example (fig. 22), and the fifth example (fig. 23) among the examples of processing described in the first embodiment can be applied.

<4.4. First modification >

Next, a first modification of the second embodiment will be described with reference to fig. 36.

In a second embodiment, a device performing D2D communication decides the size of data to be transmitted and received in D2D communication. In the case of D2D communication between slave devices in the LN, the master device does not directly engage in the D2D communication, but allocates radio resources for the D2D communication. Thus, in the second embodiment described above, the master device will allocate radio resources for D2D communication without knowing whether there is a retransmission for D2D communication between the slave devices (i.e., ACK/NACK for D2D communication between the slave devices). As a result, more radio resources than necessary are allocated to transmission of data to be retransmitted, possibly resulting in waste of radio resources. In addition, it may take time to retransmit without allocating necessary radio resources to the data to be retransmitted.

Then, according to the first modification of the second embodiment, the slave device feeds back information (e.g., ACK/NACK) on retransmission for D2D communication between the slave devices to the master device, and the master device performs resource control in consideration of the presence or absence of retransmission.

(communication control Unit 177)

In particular, in the first modification of the second embodiment, when the terminal device 100-2 is a slave device in the LN, the communication control unit 177 feeds back information on retransmission for D2D communication between the slave devices to the master device through the wireless communication unit 120. For example, ACK/NACK for D2D communication between the slave devices is fed back to the master device as information related to retransmission. Note that, for example, the radio resources for the feedback may be allocated by the master in the LN.

(radio resource information acquisition unit 171)

As described above, the terminal device 100-2 (e.g., the radio resource information acquisition unit 171) allocates radio resources for D2D communication in the LN from among radio resources reported by the base station 10 as available radio resources. The allocated radio resource becomes a D2D resource (radio resource for D2D communication). In the second embodiment, the terminal device 100-2 performs such resource allocation when it is the master in the LN.

In particular, in the first modification of the second embodiment, the terminal device 100-2 (e.g., the radio resource information acquisition unit 171) considers whether or not the D2D communication (i.e., the target transmission) between the slave devices is retransmission to allocate radio resources for the D2D communication between the slave devices. For example, when the target transmission is a retransmission, radio resources are preferentially allocated for the transmission from the point of view of time and/or the amount of resources.

(flow of processing)

Communication control processing according to the first modification of the second embodiment

Fig. 36 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the first modification of the second embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The difference between the first example according to the second embodiment shown in fig. 34 and the example according to the first modification of the second embodiment shown in fig. 36 is that in the first example according to the second embodiment, step S640 is included, whereas in the example according to the second modification of the first embodiment, steps S641 and S681 are included instead of step S640. Thus, only steps S641 and S681 are described herein.

After transmission and reception of data in D2D communication between the slave devices (S670), ACK/NACK is fed back between the terminal device 100B and the terminal device 100C performing D2D communication. Further, the ACK/NACK is fed back from the terminal apparatus 100B and/or the terminal apparatus 100C to the terminal apparatus 100A as the master terminal (S681).

Further, the terminal device 100A (radio resource information acquisition unit 171) as the master terminal considers whether or not the D2D communication (i.e., target transmission) between the terminal device 100B and the terminal device 100C as the slave devices is retransmission to allocate radio resources for the D2D communication (S641). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication. The flow of this process is described later.

In the first modification of the second embodiment, as an example of the process of allocating radio resources for D2D communication, an example of the process described in the second modification of the first embodiment with reference to fig. 27 can be applied.

The first modification of the second embodiment is explained above. According to the first modification of the second embodiment, even when a terminal device that is not involved in D2D communication directly decides the size of data, data is transmitted and received in D2D communication using a radio resource in consideration of retransmission. As a result, the efficiency of use of radio resources can be improved.

<4.5. Second modification example >

Next, a second modification of the second embodiment will be described with reference to fig. 37.

In the example of the second embodiment described above, the terminal device 100-2 as the master allocates radio resources for D2D communication in LN from among radio resources reported by the base station 10 as available radio resources.

On the other hand, in particular, in the second modification of the second embodiment, the base station 10 directly allocates radio resources for D2D communication in LN.

(radio resource information acquisition unit 171)

In particular, in the second modification of the second embodiment, radio resources (D2D resources) available for D2D communication are allocated by the base station 10 as radio resources for D2D communication and reported by the base station 10. That is, the base station 10 directly allocates radio resources for D2D communication in LN. The allocated radio resource becomes a D2D resource (radio resource usable for D2D communication). The terminal device 100-2 (e.g., the terminal device 100-2 as a master) is informed of the D2D resources.

Then, in particular, in the second modification of the second embodiment, when the terminal device 100-2 is the master device, the radio resource information acquisition unit 171 acquires information related to D2D resources to be reported to the base station 10.

(flow of processing)

Communication control processing according to a second modification of the second embodiment

Fig. 37 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to a second modification of the second embodiment. In this example, the terminal device 100B and the terminal device 100C, which are slave devices in the LN, perform D2D communication.

The difference between the first example according to the second embodiment shown in fig. 34 and the example according to the second modification of the second embodiment shown in fig. 37 is that in the first example according to the second embodiment, steps S620, S630, and S640 are included, whereas in the example according to the second modification of the second embodiment, steps S621 and S631 are included instead of these steps. Thus, only steps S621 and S631 will be described here.

When the predetermined condition is satisfied, the base station 10 allocates a part of radio resources among radio resources controllable by the base station 10 as resources for D2D communication (S621). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication.

The base station 10 then notifies the terminal device 100A as a master of D2D resources on an arbitrary channel (e.g., PDCCH, PDSCH, or PBCH) (S631).

The second modification of the second embodiment is explained above. According to the second modification of the second embodiment, the terminal device 100-2 may not reproduce the resource control, thus enabling the load on the terminal device 100-2 to be reduced.

Note that the second modification of the second embodiment may be combined with the first modification of the second embodiment. That is, in the second modification of the second embodiment, similar to the first modification of the second embodiment, information (ACK/NACK) related to importance may also be fed back to the base station 10.

<4.6. Third modification example >

A third modification of the second embodiment is described below with reference to fig. 38 to 40.

In the example of the second embodiment described above, the base station 10 notifies the terminal device 100-2 of available radio resources (for example, radio resources allocated to LN, radio resources allocated to the terminal device 100-2, radio resources not allocated, and the like). The terminal device 100-2 as the master then allocates radio resources for D2D communication in the LN from among the radio resources reported from the base station 10.

On the other hand, in particular, in the third modification of the second modification, the available radio resources are not reported by the base station 10 but estimated by the terminal device 100-2.

(radio resource information acquisition unit 171)

In particular, in the third modification, the radio resources (D2D resources) used for D2D communication are part or all of the radio resources estimated as available radio resources. For example, the radio resource information acquisition unit 171 estimates available radio resources. Subsequently, for example, the radio resource information acquisition unit 171 allocates a part or all of the estimated radio resources as radio resources for D2D communication, and acquires radio resource information related to the radio resources (i.e., D2D resources). Note that the radio resource information acquisition unit 171 may consider the estimated radio resource as a D2D resource to acquire radio resource information related to the estimated radio resource.

Note that an example of estimated radio resources, and an apparatus that performs the estimation are similar to those described in the fourth modification of the first embodiment.

(flow of processing)

Communication control process according to the third modification of the second embodiment (case where the master performs estimation)

Fig. 38 is a sequence chart illustrating a first example of a schematic flow of communication control processing according to a third modification of the second embodiment. In this example, the master device estimates available radio resources. Then, from the estimated radio resources, radio resources for D2D communication are allocated.

The difference between the first example according to the second embodiment shown in fig. 34 and the example according to the third modification of the second embodiment shown in fig. 38 is that in the first example according to the second embodiment, steps S620 and S630 are included, whereas in the first example according to the third modification of the second embodiment, step S623 is included instead of these steps. Then, step S623 is described here.

The terminal device 100A (radio resource information acquisition unit 171) as the master estimates the available radio resources (S623).

Communication control process according to the third modification of the second embodiment (case where two or more devices make estimation)

Fig. 39 is a sequence chart illustrating a second example of a schematic flow of communication control processing according to a third modification of the second embodiment. In this example, the available radio resources are estimated and shared by the master device and the slave device. Then, from among the estimated radio resources, radio resources for D2D communication are allocated.

The difference between the first example according to the third modification of the second embodiment shown in fig. 38 and the second example according to the third modification of the second embodiment shown in fig. 39 is that in the first example, step S623 is included, and in the second example, step S625 is included instead of step S623. Then, step S325 is described here.

The terminal device 100A as a master device, and the terminal device 100B and the terminal device 100C as slave devices estimate available radio resources and share the available radio resources (S625).

Communication control process according to the third modification of the second embodiment (in the case of no resource allocation)

Fig. 40 is a sequence chart illustrating a third example of a schematic flow of communication control processing according to a third modification of the second embodiment. In this example, the available radio resources are estimated by the master device. Subsequently, the estimated radio resources are regarded as radio resources (D2D resources) available for D2D communication. That is, radio resources for D2D communication are not allocated.

The difference between the first example according to the third modification of the second embodiment shown in fig. 38 and the third example according to the third modification of the second embodiment shown in fig. 40 is that in the first example, steps S623, S640, S650, and D660 are included, and in the third example, steps S627 and S661 are included instead of these steps. Thus, steps S627 and S661 are described here.

The terminal device 100B (radio resource information acquisition unit 171) estimates the available radio resources (S627). Subsequently, in this example, the estimated radio resource becomes a radio resource (D2D resource) usable for D2D communication.

The terminal device 100B notifies the terminal device 100C, which is a device on the other side of the D2D communication, of the D2D resource and the size-related information (S661).

Note that the device performing D2D communication is described above as an example of a slave device only, however, the device performing D2D communication may include a master device. Further, an example in which one device (terminal device 100B) performs the estimation is described above, however, another device (terminal device 100A or terminal device 100C) may perform the estimation, or two or more devices (for example, terminal device 100A, terminal device 100B, and terminal device 100C) may perform the estimation.

The third modification of the second embodiment is explained above. According to the third modification of the second embodiment, the base station 10 does not perform resource control for D2D communication. Thus, even when D2D communication is performed, the load of the base station 10 can be suppressed.

Third embodiment 5

A third embodiment of the present disclosure is described below with reference to fig. 41 to 46.

<5.1. Overview >

First, with reference to fig. 41, an outline of the second embodiment is explained. In the third embodiment, as a form of D2D communication, D2D communication performed alone as described above with reference to fig. 11 is adopted. That is, unlike the first embodiment and the second embodiment, LN is not employed. Then, the size of data to be transmitted and received in D2D communication is decided by the device performing D2D communication. A specific example of this will be described below with reference to fig. 41.

Fig. 41 is an explanatory diagram illustrating an outline of the third embodiment. Referring to fig. 41, there are shown 2 terminal apparatuses 100 performing D2D communication. In this example, the terminal device 100A and the terminal device 100B perform D2D communication. At least one of the terminal device 100A and the terminal device 100B performing D2D communication decides the size of data to be transmitted and received in D2D communication.

<5.2. Functional Structure of terminal device >

Referring to fig. 42, a functional structure of the terminal device 100-3 according to the third embodiment is explained. Fig. 42 is a block diagram illustrating an example of the functional structure of the terminal device 100-3 according to the third embodiment. Referring to fig. 42, the terminal device 100-3 includes an antenna unit 100, a wireless communication unit 120, a storage unit 130, an input unit 140, a display unit 150, and a processing unit 180.

Here, there is no difference between the first embodiment and the second embodiment in terms of the antenna unit 110, the wireless communication unit 120, the storage unit 130, the input unit 140, the display unit 150, and the display control unit 169 included in the processing unit 180. Then, here, a radio resource information acquisition unit 181, a data size decision unit 183, a notification unit 185, and a communication control unit 187 included in the processing unit 180 are explained.

(radio resource information acquisition unit 181)

The radio resource information acquisition unit 181 acquires information related to available radio resources.

For example, the radio resource information acquisition unit 181 acquires information on radio resources available for radio communication between the base station 10 and the terminal device 100-3 among radio resources controllable by the base station 10. The content of this point is the same as that described in the first embodiment.

Radio resources (D2D resources) available for D2D communication

In particular, in the embodiment according to the present disclosure, the radio resource information acquisition unit 181 acquires radio resource information related to radio resources (D2D resources) available for D2D communication not via the base station 10. As described above, the radio resources controllable by the base station 10 are, for example, radio resources allocable by the base station 10.

In the third embodiment, the base station 100 notifies the terminal device 100-3 of D2D resources. The radio resource information acquisition unit 181 then acquires radio resource information related to the D2D resources reported by the base station 10.

(data size determination section 183)

The data size determining unit 183 determines the size of data to be transmitted and received in D2D communication based on radio resource information related to D2D resources.

In particular, in the third embodiment, the data size decision unit 183 decides the size when the terminal device 100-3 performs D2D communication. Note that when another device performing D2D communication decides the size and notifies the terminal device 100-3 of the size, the data size decision unit 183 may not decide the size. For example, when the terminal device 100-3 is a device on the transmission side in D2D communication, the data size decision unit 183 may decide the size, whereas when the terminal device 100-3 is a device on the reception side in D2D communication, the data size decision unit 183 may not decide the size.

(notification unit 185)

The notification unit 185 notifies the other device performing D2D communication of size-related information related to the decided size. In particular, in the third embodiment, when the terminal device 100-3 performs D2D communication and decides the size, the notification unit 185 notifies the other device performing D2D communication of the size-related information.

Note that the specific contents of the size-related information to be reported, and the specific notification method are similar to those described in the first embodiment.

(communication control unit 187)

The communication control unit 187 controls wireless communication of the terminal device 100-3. For example, when the terminal device 100-3 performs wireless communication with the base station 10, the communication control unit 187 controls wireless communication of the terminal device 100-3 with the base station 10.

In particular, in an embodiment according to the present disclosure, the communication control unit 187 controls D2D communication of the terminal device 100-3. Specifically, when the terminal device 100-3 performs D2D communication, the communication control unit 187 transmits or receives data having the decided data size using a radio resource (D2D resource) available for D2D communication.

Note that in the third embodiment, when D2D communication is performed, but the size of data to be transmitted and received in the D2D communication is not decided, the terminal device 100-3 notifies size-related information by another device performing D2D communication. In this case, the terminal device 100-3 can recognize the size of data to be transmitted and received in D2D communication using a method similar to that described in the first embodiment.

<5.3. Flow of treatment >

Next, with reference to fig. 43, a communication control process according to a third embodiment is explained. Fig. 43 is a sequence diagram illustrating an example of a schematic flow of the communication control processing according to the third embodiment.

The terminal device 100 estimates the state of the channel available for D2D communication. For example, the terminal device 100 estimates the state of the channel by receiving a reference signal transmitted by another terminal device 100. Subsequently, for example, information related to the channel is fed back between the terminal apparatuses 100 performing D2D communication (S810). The information related to the channel is Channel State Information (CSI), including CQI, RI, PMI, RSRP, RSRQ, etc. Note that the information related to the channel may also be fed back to the base station 10.

Further, when the predetermined condition is satisfied, the base station 10 allocates a part of radio resources among radio resources controllable by the base station 10 to the terminal device 100 performing D2D communication (S820). Note that when information related to a channel is also fed back to the base station 10, the base station 10 may allocate radio resources in consideration of the information.

The base station 10 then notifies the terminal device 100 (i.e., the terminal device 100A and the terminal device 100B) of radio resources allocated to the terminal device performing D2D communication on an arbitrary channel (e.g., PDCCH, PDSCH, or PBCH) (S830).

Subsequently, the terminal device 100B (data size deciding unit 183) which is one of the devices performing D2D communication decides the size of data to be transmitted and received in D2D communication (S900). The flow of this process is described later.

Subsequently, the terminal device 100B (notification unit 185) notifies the other device (terminal device 100C) performing D2D communication of size-related information related to the decided size (S840). Note that D2D resources may be reported together with size related information.

After that, the terminal device 100B and the terminal device 100C transmit and receive data having the decided size using the D2D resource (S850).

In the third embodiment, as an example of the process (S900) of determining the size of data to be transmitted and received in D2D communication, the first example (fig. 19), the second example (fig. 20), the fourth example (fig. 22), and the fifth example (fig. 23) among the examples of the process described in the first embodiment can be applied.

<5.4. First modification >

Next, a first modification of the third embodiment will be described with reference to fig. 44.

In a third embodiment, a device performing D2D communication decides the size of data to be transmitted and received in D2D communication. The base station 10 does not directly engage in D2D communication, but allocates radio resources for D2D communication. Thus, in the third embodiment described above, the base station 10 will allocate radio resources for D2D communication without knowing whether there is a retransmission for D2D communication (i.e., ACK/NACK for D2D communication). As a result, more radio resources than necessary are allocated to transmission of data to be retransmitted, possibly resulting in waste of radio resources. In addition, it may take time to retransmit without allocating necessary radio resources to the data to be retransmitted.

Thus, according to the first modification of the third embodiment, the terminal device 100 performing D2D communication feeds back information (e.g., ACK/NACK) related to retransmission for D2D communication to the base station 10, and the base station 10 performs resource control in consideration of the presence or absence of retransmission.

(communication control unit 187)

In particular, in the first modification of the third embodiment, when the terminal device 100-3 performs D2D communication, the communication control unit 187 feeds back information related to retransmission concerning D2D communication to the base station 10 through the wireless communication unit 120. For example, as information related to retransmission, ACK/NACK regarding D2D communication is fed back to the base station 10. Note that, for example, radio resources for the feedback are allocated by the base station 10.

(flow of processing)

The difference between the example according to the third embodiment shown in fig. 43 and the example according to the first modification of the third embodiment shown in fig. 44 is that in the example according to the third embodiment, step S820 is included, but in the first example according to the first modification of the third embodiment, steps S821 and S861 are included instead of step S820. Thus, only steps S821 and S861 are described here.

After transmission and reception of data in D2D communication (S850), ACK/NACK is fed back between the terminal device 100A and the terminal device 100B performing D2D communication. Further, ACK/NACK is fed back from the terminal apparatus 100A and/or the terminal apparatus 100B to the base station 10 (S861).

Further, the base station 10 considers whether the D2D communication (i.e., the target transmission) between the terminal device 100A and the terminal device 100B is retransmission or not to allocate radio resources for the D2D communication (S821). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication.

The first modification of the third embodiment is explained above. According to the first modification of the third embodiment, data is transmitted and received in D2D communication using radio resources in consideration of retransmission. As a result, the efficiency of use of radio resources can be improved.

<5.5. Second modification example >

Next, a second modification of the third embodiment will be described with reference to fig. 45 and 46.

In the example of the third embodiment described above, the base station 10 notifies the terminal device 100-3 of available wireless communication (e.g., wireless resources to be allocated to the terminal device 100-3, and wireless resources not allocated).

On the other hand, in particular in the second modification of the third modification, the available radio resources are not reported by the base station 10 but estimated by the terminal device 100-3.

(radio resource information acquisition unit 181)

In particular, in the second modification, the radio resources (D2D resources) available for D2D communication are part or all of the radio resources estimated as available radio resources. For example, the radio resource information acquisition unit 181 estimates available radio resources. Subsequently, for example, the radio resource information acquisition unit 181 regards the estimated radio resource as a D2D resource to acquire radio resource information related to the estimated radio resource.

Note that an example of estimated radio resources, and an apparatus for performing estimation are similar to those described in the fourth modification of the first embodiment.

(flow of processing)

Communication control process (case of estimation by one device) according to the second modification of the third embodiment

Fig. 45 is a sequence chart illustrating a first example of a schematic flow of communication control processing according to the second modification of the third embodiment. In this example, the available radio resources are estimated by one device that is in D2D communication. Subsequently, the estimated radio resource becomes a radio resource (D2D resource) for D2D communication.

The difference between the example according to the third embodiment shown in fig. 43 and the example according to the second modification of the third embodiment shown in fig. 45 is that steps S820, S830, and S840 are included in the example according to the third embodiment, but steps S823 and S841 are included in the first example according to the third modification of the second embodiment, and steps S820, S830, and S840 are not included. Thus, only steps S823 and S841 are described here.

The terminal device 100A (radio resource information acquisition unit 181) performing D2D communication estimates available radio resources (S823).

The terminal device 100A notifies the terminal device 100B, which is the other device in the D2D communication, of the D2D resource and the size-related information (S841).

Communication control process according to the second modification of the third embodiment (case where two devices make an estimation)

Fig. 46 is a sequence chart illustrating a second example of a schematic flow of the communication control process according to the second modification of the third embodiment. In this example, the available radio resources are estimated by two devices that are in D2D communication. Subsequently, the estimated radio resource becomes a radio resource (D2D resource) for D2D communication.

The difference between the first example according to the second modification of the third embodiment shown in fig. 45 and the second example according to the second modification of the third embodiment shown in fig. 45 is that step S823 is included in the first example, but step S825 is included in the second example instead of step S823. Then, step S825 is described here.

The terminal device 100A and the terminal device 100B performing D2D communication estimate available radio resources and share the radio resources (S825).

The second modification of the third embodiment is explained above. According to the second modification of the third embodiment, the base station 10 may not perform resource control for D2D communication. Thus, even when D2D communication is performed, the load on the base station 10 can be suppressed.

Related peripheral operations >

Subsequently, with reference to fig. 47 to 53, the related peripheral operation is explained.

(upper limit of transmit power)

In general, in wireless communication between a base station and a terminal device, the terminal device performs transmission power control. In this case, the maximum value or upper limit of the transmission power of the terminal device 100 is specified. For example, an upper limit of 23dBm is specified.

Meanwhile, in D2D communication, the distance between nodes is shorter than in wireless communication between a base station and a terminal device (i.e., normal wireless communication). Thus, the transmit power of the terminal device in D2D communication may be smaller than the transmit power of the terminal device upon wireless communication between the base station 10 and the terminal device.

Thus, the upper limit of the transmission power in D2D communication can be specified separately from the upper limit of the transmission power in general wireless communication. Further, an upper limit of the transmission power in the D2D communication may be lower than that in the general wireless communication.

This can reduce interference caused by the terminal device performing D2D communication, avoiding setting of excessive power of the terminal device.

(selection of modulation scheme and coding scheme)

For example, in LTE, in wireless communication (i.e., normal wireless communication) between a base station and a terminal device, measurement information such as CQI, RI, PMI is periodically fed back from the terminal device to the base station. Then, when normal radio communication is started, a modulation scheme and a coding scheme corresponding to the channel state can be selected.

Meanwhile, in the case of employing D2D communication, when channel states between terminal devices are to be fed back in addition to channel states between the terminal devices and the base station, it may be difficult to secure radio resources for feedback.

As a countermeasure, as a first example, as described above, in D2D communication, when a predetermined modulation scheme and a predetermined coding scheme are used in the first communication, and feedback of the channel state becomes possible after the communication, an appropriate modulation scheme and coding scheme are used.

As a second example, even when feedback is impossible or absent, if reception has succeeded successively a predetermined number of times based on ACK/NACK, a modulation scheme and/or a coding scheme having a higher data rate may be used.

As a third example, even when feedback is impossible or absent, if reception has failed successively a predetermined number of times based on ACK/NACK, a modulation scheme and a coding scheme having a lower data rate may be used.

(RLC related operations)

In the case of a communication system complying with LTE, the operation of a Radio Link Control (RLC) sub-layer of layer 2 (L2) can be divided into the operation of normal wireless communication between a base station and a terminal device, and the operation of D2D communication, thereby making it possible to simplify the operation of RLC upon D2D communication even more.

Fig. 47 and 48 are explanatory diagrams illustrating the position of RLC in L2 of LTE. As shown in fig. 47, as the sub-layer of L2, medium Access Control (MAC), RLC, and packet data convergence protocol (PDPC) are represented. RLC has 3 modes such as a Transparent Mode (TM), a Unacknowledged Mode (UM), and an Acknowledged Mode (AM). Each mode is associated with a logical channel that is an interface between the RLC and the slave MAC. Further, as shown in fig. 48, RLC exists in both eNodeB and UE. Note that the main functions of RLC include integration and segmentation of data to be exchanged with a subordinate MAC, repetition detection of data delivered from a MAC, ARQ, and the like.

The RLC mode and logical channel are associated with the type of data (control data, user data, etc.). In D2D communication, user data is basically considered to be transmitted and received between terminal devices. Then, in D2D communication, only a part of the logical channel prepared for normal wireless communication (i.e., wireless communication between the base station and the terminal device) will be used.

Thus, in D2D communication, the mode of the logical channel and RLC may be limited in advance, so that RLC may be simplified, and so that error processing may be performed when improper data is delivered to RLC.

Fig. 49 is a flowchart illustrating an example of a schematic flow of processing of RLC when D2D communication is employed. First, it is determined whether data of D2D communication is received (S1110), and if data of D2D communication is not obtained, normal RLC processing is performed (S1160). When the data of the D2D communication is obtained, it is determined whether the data of the logical channel used in the D2D communication is received (S1120). When the received data is not data of the logical channel, the data is discarded and error processing is performed (S1150). Further, it is determined whether or not data of RLC mode used in D2D communication is received (S1130), and when the received data is not data of RLC mode, the data is discarded and error processing is performed (S1150). On the other hand, when the received data is data of RLC mode, processing according to RLC mode is performed (S1140).

As a first example, in D2D communication, only UM and AM are used in RLC mode. In this case, for example, instead of using a logical channel related to cell control, only a Multicast Control Channel (MCCH), a Multicast Traffic Channel (MTCH), a Dedicated Control Channel (DCCH), and a Dedicated Traffic Channel (DTCH) are used. Further, as a second example, in D2D communication, only AM is used in RLC mode. In this case, the logical channels related to cell control are not used, and only DCCH and DTCH are used.

(number of HARQ Process)

Number of HARQ processes working simultaneously

In LTE, retransmission in units of transport blocks is possible. When one transport block is generated for a new transmission, the one transport block is bundled onto one HARQ process. In the HARQ process, a series of operations of transmission and reception, ACK/NACK, retransmission/reception (if necessary) are repeated until a predetermined condition is satisfied. The predetermined condition is that correct reception of the transport block is completed, an upper limit of the number of retransmissions is reached, a timer expires, etc.

The maximum number of HARQ processes operating simultaneously is specified. For example, in FDD, the maximum number of HARQ processes in downlink and uplink is 8, respectively. On the other hand, in TDD, the maximum number is specified for each TDD configuration.

Fig. 50 is an explanatory diagram illustrating the maximum number of HARQ processes related to the downlink of TDD. In the 3GPP technical standard (TS 36.213), as shown in fig. 50, a maximum number of HARQ processes for downlink data is specified for each TDD configuration. The use of the maximum number of HARQ processes allows downlink data to be transmitted and received in each downlink subframe without any loss of use of radio resources in the downlink subframe.

Separation of maximum number of HARQ processes

As a first example, in general wireless communication (i.e., wireless communication between a base station and a terminal device) and D2D communication, the maximum number of HARQ processes may be set, respectively. This makes it possible to reduce the influence on the usual wireless communication even when D2D communication is employed.

Further, the maximum number of HARQ processes for D2D communication may be set to a value smaller than the maximum number of HARQ processes for general wireless communication. This is because it is considered that in D2D communication, the possibility of a plurality of applications operating is low, and thus the number of HARQ processes operating simultaneously is also small. As a result, it is possible to reduce the amount of memory required for the HARQ process and suppress power consumption caused by the operation of the HARQ process.

Fig. 51 is a flowchart illustrating an example of a schematic flow of control processing when the maximum number of HARQ processes is set in each of normal wireless communication and D2D communication. When a transport block to be transmitted with D2D communication is generated using this process (S1260), HARQ processes for D2D communication are generated, and the number of D2D HARQ processes is incremented (S1265). When a transport block to be transmitted with normal wireless communication (wireless communication between a base station and a terminal device) is generated (S1270), HARQ processes of the normal wireless communication are generated, and the number of normal HARQ processes is incremented (S1275).

-synthesis of maximum number of HARQ processes

As a second example, the maximum number may be set for the total value of the number of HARQ processes for normal wireless communication (i.e., wireless communication between the base station and the terminal device) and the number of HARQ processes for D2D communication.

Fig. 52 is a flowchart illustrating an example of a schematic flow of control processing when the maximum number of HARQ processes is set in both normal wireless communication and D2D communication. Even when the HARQ process of D2D communication is generated with such a process (S1370), and even when the HARQ process of normal wireless communication is generated with such a process (S1375), the number of common HARQ processes is incremented (S1380).

Retransmission of HARQ processes without D2D communication

Note that in D2D communication, retransmission using the HARQ process may not be performed. This is because it is considered that D2D communication is likely to be wireless communication of a shorter distance, so that the propagation state is more stable. As a first example of a specific method, the number of retransmissions in the HARQ process may be set to 0. Further, as a second example, for D2D communication, HARQ processes may not be generated.

Fig. 53 is a flowchart illustrating an example of a schematic flow of control processing when no HARQ process is generated for D2D communication. Even when a transport block for D2D communication is generated by such processing (S1440, S1450), the HARQ process for D2D communication is not generated. On the other hand, the HARQ process of the normal wireless communication is generated (S1460), and the number of HARQ processes is incremented according to the generation (S1470).

If the HARQ process is not generated for D2D communication in this way, it is possible to reduce the amount of memory required for the HARQ process and suppress power consumption caused by the operation of the HARQ process.

Parameters of HARQ process

Parameters (timer, number of retransmissions, etc.) may differ between the HARQ process of normal wireless communication and the HARQ process of D2D communication. For example, in D2D communication, the frequency of radio resource allocation is low, so that a long timer can be set. Further, for example, in D2D communication, it is considered that the communication distance is short and the change in the propagation environment is small, so that the number of retransmissions can be set small.

Operation of HARQ processes in nodes not in D2D communication

As described above, ACK/NACK for D2D communication may also be fed back to nodes (e.g., base stations, master devices) that do not directly conduct D2D communication. In this case, for example, a HARQ process or other equivalent process may be generated and operated. In addition, such a process may manage the number of retransmissions, a timer, the size of the transmitted data, etc. Further, such a process may update the management information according to information from the device performing D2D communication.

Nodes that do not directly perform D2D communication may consider the number of HARQ processes when allocating radio resources for D2D communication. For example, when the number of HARQ processes does not reach the maximum number, radio resources for D2D communication may be newly allocated, and when the number of HARQ processes reaches the maximum number, radio resources for D2D communication may not be newly allocated.

Application example >

The techniques according to embodiments of the present disclosure may be applicable to a variety of products. For example, the terminal device 100 may be implemented as a mobile terminal such as a smart phone, a tablet Personal Computer (PC), a notebook PC, a portable game terminal, a portable/adapter type mobile router and a digital camera, or a vehicle-mounted terminal such as a vehicle-mounted navigation device. The terminal device 100 may also be implemented as a terminal (also referred to as a Machine Type Communication (MTC) terminal) that performs inter-machine (M2M) communication. In addition, at least a portion of the elements of terminal device 100 may be implemented as wireless communication modules (e.g., integrated circuit modules comprising a single die) mounted on the respective terminals.

(first application example)

Fig. 54 is a block diagram illustrating an example of a schematic structure of a smartphone 1800 to which the technology of the present disclosure is applicable. The smartphone 1800 includes a processor 1801, memory 1802, storage 1803, an external connection interface 1804, a camera 1806, a sensor 1807, a microphone 1808, an input device 1809, a display device 1810, a speaker 1811, a wireless communication interface 1812, one or more antenna switches 1815, one or more antennas 1816, a bus 1817, a battery 1818, and an auxiliary controller 1819.

The processor 1801 may be, for example, a CPU or a system on a chip (SoC) that controls the functions of the application layer and another layer of the smartphone 1800. The memory 1802 includes RAM and ROM, and holds programs executed by the processor 1801, as well as data. The memory 1803 may include a storage medium such as a semiconductor memory and a hard disk. The external connection interface 1804 is an interface for connecting external devices such as a memory card and a Universal Serial Bus (USB) device to the smart phone 1800.

The camera 1806 includes an image sensor such as a Charge Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS), and generates a photographed image. The sensor 1807 may include a group of sensors such as a measurement sensor, a gyro sensor, a geomagnetic sensor, and an acceleration sensor. The microphone 1808 converts sound input to the smartphone 1800 into an audio signal. The input device 1809 includes, for example, a touch sensor, keypad, keyboard, buttons, or switches configured to detect touches on the screen of the display device 1810, receiving operations or information input from a user. The display device 1810 includes a screen such as a Liquid Crystal Display (LCD) and an Organic Light Emitting Diode (OLED) display, displaying an output image of the smartphone 1800. The speaker 1811 converts audio signals output from the microphone 1808 into sound.

The wireless communication interface 1812 supports any cellular communication means such as LTE and LTE-Advanced, and performs wireless communication. The wireless communication interface 1812 may generally include, for example, a BB processor 1813 and RF circuitry 1814. The BB processor 1813 can perform, for example, encoding/decoding, modulation/demodulation, and multiplexing/demultiplexing, and performs various signal processing for wireless communication. Meanwhile, the RF circuit 1814 may include, for example, mixers, filters, and amplifiers for transmitting and receiving wireless signals through the antenna 1816. The wireless communication interface 1812 may also be a monolithic module integrating the BB processor 1813 and the RF circuitry 1814. The wireless communication interface 1812 may include a plurality of BB processors 1813 and a plurality of RF circuits 1814 as illustrated in fig. 54. Note that fig. 54 illustrates an example in which the wireless communication interface 1812 includes a plurality of BB processors 1813 and a plurality of RF circuits 1814, however, the wireless communication interface 1812 may also include a single BB processor 1813 or a single RF circuit 1814.

In addition, the wireless communication interface 1812 may support another wireless communication method, such as a short-range wireless communication method, a near-field wireless communication method, and a wireless Local Area Network (LAN) method, in addition to the cellular communication method. In this case, the wireless communication interface 1812 may include a BB processor 1813 and RF circuitry 1814 for each wireless communication mode.

Each antenna switch 1815 switches the connection destination of the antenna 1816 between a plurality of circuits (e.g., circuits for different wireless communication modes) included in the wireless communication interface 1812.

Each antenna 1816 includes a single or multiple antenna elements (e.g., multiple antenna elements included in a MIMO antenna) for use by the wireless communication interface 1812 in transmitting and receiving wireless signals. The smartphone 1800 may include a plurality of antennas 1816 as illustrated in fig. 54. Although fig. 54 illustrates an example in which smartphone 1800 includes multiple antennas 1816, smartphone 1800 may also include a single antenna 1816.

In addition, the smartphone 1800 may include an antenna 1816 for each wireless communication mode. In this case, the antenna switch 1815 may be omitted from the structure of the smartphone 1800.

The bus 1817 interconnects the processor 1801, the memory 1802, the storage 1803, the external connection interface 1804, the camera 1806, the sensor 1807, the microphone 1808, the input device 1809, the display device 1810, the speaker 1811, the wireless communication interface 1812, and the auxiliary controller 1819. The battery 1818 supplies power to the respective components of the smartphone 1800 illustrated in fig. 54 through a feeder partially shown as a broken line in the drawing. The secondary controller 1819 operates the minimal necessary functions of the smartphone 1800, for example, in sleep mode.

In the smart phone 1800 illustrated in fig. 54, the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165) described with reference to fig. 13 may be implemented in the wireless communication interface 1812. Further, at least a portion of these constituent elements may be implemented in the processor 1801 or the auxiliary controller 1819. For example, the smart phone 1800 may install a module including part (e.g., the BB processor 1813) or all of the wireless communication interface 1812, the processor 1801, and/or the auxiliary controller 1819, in which the radio resource information acquisition unit 161 and the data size decision unit 163 (and notification unit 165) may be implemented. In this case, the module may hold a program that allows the processor to function as the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), in other words, a program that allows the processor to execute the operations of the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), and may execute the program. For another example, a program allowing the processor to function as the radio resource information acquiring unit 161 and the data size deciding unit 163 (and the notifying unit 165) is installed to the smart phone 1800, and the wireless communication interface 1812 (for example, the BB processor 1813), the processor 1801 and/or the auxiliary controller 1819 can execute the program. As described above, as the device including the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), the smart phone 1800 or the module may be provided, and a program that allows the processor to function as the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165) may be provided. Further, a readable recording medium storing the program may be provided. In these points, the radio resource information acquisition unit 171 and the data size determination unit 173 (and the notification unit 175) described above with reference to fig. 33 are also similar to the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165), and the radio resource information acquisition unit 181 and the data size determination unit 183 (and the notification unit 185) described above with reference to fig. 42 are also similar to the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165).

(second application example)

Fig. 55 is a block diagram illustrating an example of a schematic structure of a vehicle-mounted navigation apparatus 1820 to which the technology of the present disclosure is applied. The in-vehicle navigation device 1820 includes a processor 1821, memory 1822, a Global Positioning System (GPS) module 1824, a sensor 1825, a data interface 1826, a content player 1827, a storage media interface 1828, an input device 18218, a display device 1830, a speaker 1831, a wireless communication interface 1833, one or more antenna switches 1836, one or more antennas 1837, and a battery 1838.

The processor 1821 may be, for example, a CPU or SoC, control the navigation function and another function of the in-vehicle navigation device 1820. The memory 1822 includes RAM and ROM, and stores programs executed by the processor 1821, as well as data.

The GPS module 1824 measures the location (e.g., latitude, longitude, and altitude) of the vehicle navigation device 1820 using GPS signals received from GPS satellites. The sensor 1825 may include a set of sensors such as a gyroscopic sensor, a geomagnetic sensor, and a barometric sensor. The data interface 1826 is connected to, for example, the in-vehicle network 1841 via a terminal not shown, and obtains vehicle-generated data, such as vehicle speed data.

The content player 1827 reproduces content stored in a storage medium (such as a CD and a DVD) inserted in the storage medium interface 1828. The input device 1829 includes, for example, a touch sensor, button, or switch configured to detect a touch on the screen of the display device 1830, receives an operation or information input from a user. The display device 1830 includes a screen such as an LCD or OLED display, displaying navigation functions or images of reproduced content. The speaker 1831 outputs a navigation function or sound of reproduced content.

The wireless communication interface 1833 supports any cellular communication means, such as LTE and LTE-Advanced, for wireless communication. The wireless communication interface 1833 may generally include, for example, a BB processor 1834 and RF circuitry 1835. The BB processor 1834 may perform, for example, encoding/decoding, modulation/demodulation, and multiplexing/demultiplexing, performing various signal processing for wireless communication. Meanwhile, the RF circuit 1835 may include, for example, a mixer, a filter, and an amplifier, transmitting and receiving a wireless signal through the antenna 1837. The wireless communication interface 1833 may be a monolithic module integrating the BB processor 1834 and the RF circuitry 1835. The wireless communication interface 1833 may include a plurality of BB processors 1834 and a plurality of RF circuits 1835, as illustrated in fig. 55. Note that fig. 55 illustrates an example in which the wireless communication interface 1833 includes a plurality of BB processors 1834 and a plurality of RF circuits 1835, however, the wireless communication interface 1833 may also include a single BB processor 1834 or a single RF circuit 1835.

Further, the wireless communication interface 1833 may support another wireless communication method, such as a short-range wireless communication method, a near-field wireless communication method, or a wireless LAN method, in addition to the cellular communication method. In this case, the wireless communication interface 1833 may include a BB processor 1834 and RF circuitry 1835 for each wireless communication mode.

Each antenna switch 1836 switches the connection destination of the antenna 1837 between a plurality of circuits (for example, circuits for different wireless communication modes) included in the wireless communication interface 1833.

Each antenna 1837 includes a single or multiple antenna elements (e.g., multiple antenna elements included in a MIMO antenna) for use by wireless communication interface 1833 in transmitting and receiving wireless signals. The in-vehicle navigation device 1820 may include a plurality of antennas 1837 as illustrated in fig. 55. Note that fig. 55 illustrates an example in which the in-vehicle navigation device 1820 includes a plurality of antennas 1837, however, the in-vehicle navigation device 1820 may also include a single antenna 1837.

Further, the in-vehicle navigation device 1820 may include an antenna 1837 for each wireless communication mode. In this case, the antenna switch 1836 may be omitted from the structure of the in-vehicle navigation device 1820.

The battery 1838 supplies power to each component of the in-vehicle navigation device 1820 illustrated in fig. 55 through a power supply line partially indicated as a broken line in the drawing. The battery 1838 accumulates electric power supplied from the vehicle.

In the in-vehicle navigation apparatus 1820 illustrated in fig. 55, the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165) described with reference to fig. 13 may be implemented in the wireless communication interface 1833. Further, at least a portion of these constituent elements may be implemented in the processor 1821. For example, the in-vehicle navigation apparatus 1820 may install a module including part (e.g., the BB processor 1834) or all of the wireless communication interface 1833, and/or the processor 1821, in which the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165) may be implemented. In this case, the module may hold a program that allows the processor to function as the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), in other words, a program that allows the processor to execute the operations of the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), and may execute the program. For another example, a program that allows the processor to function as the radio resource information acquiring unit 161 and the data size deciding unit 163 (and the notifying unit 165) is installed to the in-vehicle navigation device 1820, the wireless communication interface 1833 (e.g., the BB processor 1834), and/or the processor 1821 may execute the program. As described above, as the device including the radio resource information acquiring unit 161 and the data size deciding unit 163 (and the notifying unit 165), the in-vehicle navigation device 1820 or the module may be provided, and a program that allows the processor to function as the radio resource information acquiring unit 161 and the data size deciding unit 163 (and the notifying unit 165) may be provided. Further, a readable recording medium storing the program may be provided. In these points, the radio resource information acquisition unit 171 and the data size determination unit 173 (and the notification unit 175) described above with reference to fig. 33 are also similar to the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165), and the radio resource information acquisition unit 181 and the data size determination unit 183 (and the notification unit 185) described above with reference to fig. 42 are also similar to the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165).

The techniques of this disclosure may also be implemented as an in-vehicle system (or vehicle) 1840 that includes one or more components of in-vehicle navigation device 1820, in-vehicle network 1841, and vehicle module 1842. That is, as a device including the radio resource information acquisition unit 161 and the data size determination unit 163 (and the notification unit 165) (or the radio resource information acquisition unit 171 and the data size determination unit 173 (and the notification unit 175), or the radio resource information acquisition unit 181 and the data size determination unit 183 (and the notification unit 185)), an in-vehicle system (or a vehicle) 1840 may be provided. The vehicle module 1842 generates vehicle data such as vehicle speed, engine speed, and fault information, and outputs the generated data to the in-vehicle network 1841.

<8. Summary >

Up to this point, a terminal device, a communication control device (e.g., a base station), and respective processes according to an embodiment of the present disclosure are explained using fig. 9 to 55. According to an embodiment of the present disclosure, the terminal device 100 capable of communicating with the base station 10 obtains radio resource information related to radio resources (D2D resources) available for D2D communication not via the base station 10, and decides the size of data to be transmitted and received in D2D communication according to the radio resource information.

This makes it possible to suppress an increase in load on the base station 10 when D2D communication is performed.

More specifically, when the base station 10 decides the size of data to be transmitted and received in D2D communication, the base station 10 will collect various information related to D2D communication. As a result, overhead for information collection of the base station may be increased. In addition, a heavy load on the management and control of D2D communication may be imposed on the base station. However, as described above, when the terminal device 100, not the base station 10, decides the size of data, information collection, management, and control of the base station 10 are reduced, thereby enabling suppression of an increase in load on the base station 10.

Notification of size related information

Further, for example, another device performing D2D communication is notified of size-related information related to the decided size.

This enables the use of the decided size in D2D communication.

-the channel used

This enables the decided size to be notified or notified also in D2D communication, similarly to wireless communication between the base station 10 and the terminal device 100.

This enables the decided size to be notified even when the information cannot be successfully transmitted on the control channel.

This enables a larger size to be notified, as compared with the case of transmitting information corresponding to a predetermined size (e.g., index), thus improving throughput in D2D communication.

Determination of the size of the data

-decisions based on modulation scheme and coding scheme

The size is determined, for example, further based on at least one of a modulation scheme and a coding scheme.

As a first example, the modulation scheme and the coding scheme are those to be used in D2D communication by a device performing D2D communication.

In this way, when the size of data is determined also according to the modulation scheme and the coding scheme actually used, the size of data that can be transmitted can be calculated more accurately, thereby enabling a larger value to be determined as the size of data.

Note that, for example, when the terminal device 100 is not a device that performs D2D communication, channel information relating to a channel to be used in D2D communication is obtained, and from this information, a modulation scheme and a coding scheme to be used in D2D communication are identified.

This enables identification of the modulation scheme and the coding scheme to be used even when the terminal device 100 is not a device performing D2D communication.

As a second example, when the terminal apparatus 100 is not an apparatus for performing D2D communication, the modulation scheme and the coding scheme are a predetermined modulation scheme and a predetermined coding scheme.

In this way, the data size is also determined according to the predetermined modulation scheme and the predetermined coding scheme, so that information on a channel to be used in D2D communication is not required. Thus, it is not necessary to feed back channel-related information from the slave device to the master device. As a result, overhead can be reduced. Further, as another point of view, such a decision enables the size of the data to be decided even when the information related to the channel is not successfully obtained.

Note that, for example, the predetermined modulation scheme is a modulation scheme having the lowest data rate among a plurality of available modulation schemes, and the predetermined coding scheme is a coding scheme having the lowest data rate among a plurality of available coding schemes.

This makes it possible to transmit and receive data more surely. For example, even when the state of a channel to be used in D2D communication is poor, data can be correctly transmitted and received.

-a decision based on the number of radio resources

As a first example, the number of data resources available for transmission and reception of data among D2D resources is calculated based on radio resource information related to the D2D resources. Then, the size is determined based on the number of data resources and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

As a second example, a minimum size among one or more predetermined sizes corresponding to at least one of the modulation scheme and the coding scheme, and the number of D2D resources is determined as the size based on radio resource information related to the D2D resources and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

In this way, the terminal device 100 may not count the number of data resources available for transmission of data, thereby enabling suppression of the load on the terminal device 100.

Reference example ]

With additional reference to fig. 56-61, a reference embodiment is described.

<9.1. Overview >

In the various embodiments of the present disclosure described above, the size of data to be transmitted and received in D2D communication is decided by the terminal device 100. On the other hand, in the reference embodiment, the size of data to be transmitted and received in D2D communication is decided by the base station 10.

<9.2. Functional Structure of base station >

Referring to fig. 56, an example of the functional structure of the base station 10 according to the reference embodiment is explained. Fig. 56 is a block diagram illustrating an example of the functional structure of the base station 10 according to the reference embodiment. Referring to fig. 56, the base station 10 includes an antenna unit 210, a wireless communication unit 220, a storage unit 230, and a processing unit 240.

(antenna element 210)

The antenna unit 210 receives a wireless signal and outputs the received wireless signal to the wireless communication unit 220. In addition, the antenna unit 210 transmits a transmission signal output by the wireless communication unit 220.

(Wireless communication Unit 220)

The wireless communication unit 220 performs wireless communication with another device. For example, the wireless communication unit 220 performs wireless communication with the terminal device 100 placed in the cell 11.

(storage unit 230)

The storage unit 230 holds programs and data for operating the base station 10.

For example, the storage unit 230 holds information about the size of data to be transmitted and received in wireless communication. More specifically, for example, the storage unit 230 holds a table of candidate TBSs as shown in fig. 5. Further, for example, the storage unit 230 holds a table of correspondence between MCS indexes and TBS indexes as shown in fig. 7 and 8. Further, the storage unit 230 holds a table of CQI as shown in fig. 6.

(processing unit 240)

The processing unit 240 provides various functions of the base station 10. The processing unit 240 includes a resource allocation unit 241, a data size decision unit 243, and a notification unit 245.

(resource allocation unit 241)

Radio resources for wireless communication between a base station and a terminal device

The resource allocation unit 241 allocates, from among radio resources controllable by the base station 10, radio resources for radio communication between the base station 10 and the terminal device 100 to the terminal device 10. Specifically, for example, the base station 10 allocates radio resources to the terminal device 100 for downlink transmission of data delivered to the terminal device 100. Further, the base station 10 allocates radio resources to the terminal device 100 for uplink transmission of the terminal device 100.

-radio resources for D2D communication

The resource allocation unit 241 allocates radio resources for D2D communication to the terminal device 100 performing D2D communication from among radio resources controllable by the base station 10. The radio resources for D2D communication allocated in this way become radio resources (D2D resources) available for D2D communication.

The radio resource allocated for D2D communication becomes a transmission radio resource of the terminal device 100 on the transmission side of D2D communication, and becomes a reception radio resource of the terminal device 100 on the reception side of D2D communication. For example, resource allocation section 241 allocates a radio resource for D2D communication as a radio resource for transmission to terminal device 100 on the transmission side of D2D communication, and allocates a radio resource for reception as a radio resource for reception to terminal device 100 on the reception side of D2D communication.

Further, for example, when the predetermined condition is satisfied, the resource allocation unit 241 allocates a radio resource as a radio resource for D2D communication. For example, the predetermined condition is that a resource allocation request is received from the terminal device 100 performing D2D communication. For example, the request includes an ID of the terminal device 100 on the other side of the D2D communication, a total amount of data, and an application type (e.g., qoS) of the data. Further, for another example, when a service of performing D2D communication at a predetermined timing is provided, the predetermined condition is that the predetermined timing is reached. Further, for another example, the predetermined condition may be that retransmission is required due to an error occurring in D2D communication.

In addition, radio resources for transmission and reception of ACK/NACK may also be allocated along with radio resources for transmission and reception of data. The time interval between the radio resources for transmission and reception of data and the radio resources for transmission and reception of ACK/NACK may be a predetermined time interval or may be specified at any time. When the time interval is a predetermined time interval, notification of radio resources for transmission and reception of ACK/NACK is not required, resulting in reduction of overhead. The base station 10 may not allocate radio resources for transmission and reception of ACK/NACK for another wireless communication.

(data size determination section 243)

The data size decision unit 243 decides the size of data to be transmitted and received in D2D communication, based on information related to the radio resources allocated for D2D communication. For example, the information related to the allocated radio resources for D2D communication is information indicating the allocated radio resources for D2D communication.

-size to be determined

As a second example, the size to be decided is a size calculated from information related to the radio resources allocated for D2D communication.

-decisions based on modulation scheme and coding scheme

For example, data size determining section 243 further determines the size according to at least one of the modulation scheme and the coding scheme. For example, data size determining section 243 determines the size based on information on radio resources allocated for D2D communication, and a modulation scheme and a coding scheme.

As a first example, the modulation scheme and the coding scheme are those to be used in D2D communication by the terminal device 100 performing D2D communication. In this way, when the size of data is decided according to the modulation scheme and/or coding scheme to be actually used, the size of data that can be transmitted can be calculated more accurately. Thus, a larger value can be determined as the size of the data.

Note that, for example, the data size determining unit 243 obtains channel information on a channel to be used in D2D communication, and identifies a modulation scheme and a coding scheme to be used in D2D communication based on the information. The information related to the channel is, for example, channel State Information (CSI). The CSI includes CQI. The data size decision unit 243 then identifies the modulation scheme and coding scheme corresponding to the CQI. This allows the base station 10 to identify the modulation scheme and coding scheme to be used in D2D communication.

As a second example, the modulation scheme and the coding scheme are a predetermined modulation scheme and a predetermined coding scheme. Such a decision based on the predetermined modulation scheme and the data size of the predetermined coding scheme does not require information about the channel to be used in D2D communication. Thus, it is not necessary to feed back channel-related information from the terminal device 100 performing D2D communication to the base station 10. As a result, overhead can be reduced. Further, as another point of view, such a decision enables the size of the data to be decided even when the information related to the channel is not successfully obtained.

-a decision based on the number of radio resources

-a decision based on the number of resources for data

As a first example, the data size decision unit 243 calculates the number of data resources available for transmission and reception of data in the allocated radio resources, based on information on the allocated radio resources for D2D communication. The data size determining unit 243 then determines the size based on the number of data resources and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

For example, the data size decision unit 243 calculates the number of Resource Elements (REs) available for transmission and reception of data in the allocated radio resources for D2D communication as the number of resources for data. For example, the data size decision unit 243 calculates the number of REs other than REs for control signals (e.g., synchronization signals, reference signals, and signals of control channels) among radio resources allocated for D2D communication. The data size decision unit 243 then decides the size according to the calculated number of resources for data (i.e., the number of REs), and the modulation scheme and coding scheme.

Further, more specifically, for example, the data size decision unit 243 calculates the maximum value of the size of data to be transmitted, based on the calculated number of resources for data (i.e., the number of REs), and the modulation scheme and the coding scheme. The data size decision unit 243 then decides one of a plurality of predetermined sizes as the size of data to be transmitted and received in D2D communication, based on the calculated maximum value. For example, the plurality of predetermined sizes are candidate TBSs shown in fig. 5. The data size decision unit 243 then decides, as the size, a candidate equal to or smaller than the calculated maximum value among the candidate TBSs. For example, when the table shown in fig. 5 is provided, a column to be referred to in the table is decided according to the number of available radio resources (e.g., the number of RBs). Then, since the range of TBS index is decided according to the modulation scheme and the coding scheme, one or more rows to be referred to in the table are decided. Then, a candidate TBS equal to or smaller than the maximum value among some candidate TBSs corresponding to the one column and the one or more rows is first selected. Further, the largest candidate TBS among the selected candidate TBSs is finally selected. Thus, the largest candidate TBS among the candidate TBSs equal to or smaller than the calculated maximum value is selected. The first selected candidate TBS is determined as the size of data to be transmitted and received in the D2D communication.

-a decision based on the amount of radio resources allocated for D2D communication

As a second example, data size determining section 243 determines, as the size, the smallest size among one or more predetermined sizes corresponding to at least one of the modulation scheme and the coding scheme, and the number of radio resources allocated for D2D communication, based on radio resource information on the radio resources allocated for D2D communication and at least one of the modulation scheme and the coding scheme (modulation scheme and/or coding scheme).

For example, data size determining section 243 determines the minimum candidate TBS among the candidate TBSs corresponding to the modulation scheme and the coding scheme, which is the number of radio resources allocated for D2D communication, as the size of data to be transmitted and received in D2D communication. As described above, for example, when the table shown in fig. 5 is provided, a column to be referred to in the table is decided according to the number of radio resources allocated for D2D communication (i.e., the number of RBs). Then, since the range of TBS index is decided according to the modulation scheme and the coding scheme, one or more rows to be referred to in the table are decided. Then, among some candidate TBSs corresponding to the one column and the one or more rows, the smallest candidate TBS is selected. The selected candidate TBS is then determined as the size of the data to be transmitted and received in the D2D communication.

In this way, the base station 10 may not count the number of data resources available for transmission of data, thereby enabling the load of the base station 10 to be reduced.

As described above, the size of data to be transmitted and received in D2D communication is decided. This makes it possible to suppress an increase in the load of the terminal device 100 when D2D communication is performed. That is, similar to the wireless communication between the base station 10 and the terminal device 100, the terminal device 100 performing D2D communication can transmit data having a certain size by using the allocated wireless resources, thereby enabling to suppress processing that should be performed by the terminal device 100 for D2D communication.

(Notification unit 245)

Notification of allocated radio resources for D2D communication

The notification unit 245 notifies the terminal device 100 performing D2D communication of the radio resources allocated for D2D communication. For example, notification section 245 notifies radio resource to terminal device 100 performing D2D communication on a control channel (for example, PDCCH) or a data channel (for example, PDCCH) through radio communication section 220.

For example, the notification unit 245 notifies the device on the transmission side in D2D communication of the radio resource for D2D communication as the allocation of the transmission resource. For example, the notification unit 245 notifies the wireless resource to the device on the transmission side in the D2D communication in the form of uplink access permission. For example, the notification unit 245 notifies the device on the receiving side in D2D communication of the radio resource for D2D communication as the allocation of the reception resource. For example, the notification unit 245 notifies the wireless resource to the device on the receiving side in D2D communication in the form of downlink allocation.

Such notification provides for proper transmission and reception in D2D communications, for example.

Specifically, in D2D communication, one terminal device 100 performs transmission, and the other terminal device 100 performs reception. Thus, it is difficult for the terminal device 100 to know whether it should transmit or receive only from the notification of the radio resource for D2D communication. As a result, there is a possibility that transmission and reception are not properly performed in D2D communication.

Thus, if the terminal device 100 on the transmission side is notified of the allocated radio resource as the transmission radio resource and the terminal device on the reception side is notified of the allocated radio resource as the reception radio resource, the terminal device 10 can know which one of transmission and reception should be performed. As a result, in D2D communication, transmission and reception can be performed correctly.

Notification of the data size to be decided

The notification unit 245 notifies the terminal device 100 performing D2D communication of size-related information related to the decided size.

-size related information

-information corresponding to a predetermined size

Information indicating size

Specifically, as described above, for example, the decided size is a size calculated from radio resource information related to the radio resources allocated for D2D communication. The calculated size is then determined as the size of the data to be transmitted and received in the D2D communication. In this case, the size-related information is a calculated and decided size.

-the channel used

-control channel

As a first example, the terminal device 100 performing D2D communication is notified of size-related information by transmission on a control channel for transmitting a control signal. For example, the control channel is PDCCH.

The use of the control channel in this manner enables the decided size to be notified or informed also in D2D communication as in the case of wireless communication between the base station 10 and the terminal device 100.

As a second example, the size-related information is notified to another device by transmission over a data channel for transmitting data. For example, the data channel is PDSCH.

As described above, the terminal device 100 performing D2D communication is notified of the size-related information, thereby making it possible to use the decided size in D2D communication.

The functional structure of the base station 10 according to the reference embodiment is explained above. Note that such a functional structure can also be used as a functional structure of the base station 10 according to the embodiment of the present disclosure by excluding the data size deciding unit 243, and the notifying portion of the data size in the notifying unit 245.

<9.3. Flow of treatment >

An example of the communication control process according to the reference embodiment is described below with reference to fig. 57. Fig. 57 is a sequence diagram illustrating an example of a schematic flow of communication control processing according to the reference embodiment.

The terminal device 100 estimates the state of the channel available for D2D communication. For example, the terminal device 100 estimates the state of the channel by receiving a reference signal transmitted by another terminal device 100. Subsequently, for example, the terminal device 100 feeds back channel-related information to the base station 10 (S1510). The information related to the channel is Channel State Information (CSI), including CQI, RI, PMI, RSRP, RSRQ, etc.

Further, when the predetermined condition is satisfied, the base station 10 (resource allocation unit 241) allocates a radio resource, which is a part of radio resources controllable by the base station 10, to the terminal device 100 performing D2D communication as a radio resource for D2D communication (step S1520). Note that the base station 10 may allocate radio resources in consideration of the information related to the channel.

The base station 10 (data size decision unit 243) then decides the size of data to be transmitted and received in D2D communication (S1530). The flow of this process is described later.

The base station 10 (notification unit 245) then notifies the terminal device 100 performing D2D communication of the radio resource allocated for D2D communication and the size-related information related to the decided size (S1540). For example, the base station 10 (notification unit 245) notifies the terminal device 100 of radio resource and size-related information on a control channel (for example, PDCCH) or a data channel (for example, PDSCH).

After that, the terminal device 100A and the terminal device 100B transmit and receive data having a predetermined size using the allocated radio resources for D2D communication (S1550).

Note that in the reference embodiment, as an example of the process (S1530) of determining the size of data to be transmitted and received in D2D communication, processes similar to the first example (fig. 19), the second example (fig. 20), the third example (fig. 21), the fourth example (fig. 22), and the fifth example (fig. 23) among the examples of the process described in the first embodiment of the present disclosure can be applied.

<9.4. First modification >

Next, a first modification of the reference embodiment will be described with reference to fig. 58.

In the reference embodiment, the base station 10 does not directly relate to D2D communication, but determines the size of data to be transmitted and received in D2D communication. Thus, in the above-described reference embodiment, the base station 10 will decide the size of data to be transmitted and received in D2D communication without knowing whether there is retransmission for D2D communication between the terminal devices 100 (i.e., ACK/NACK for D2D communication between the terminal devices 100). That is, the base station 10 cannot determine the size of data in consideration of retransmission in D2D communication. On the other hand, when HARQ is used, in the case of retransmission, the data is required to have the same size as that of the latest transmission.

Thus, according to the first embodiment of the reference embodiment, the terminal device 100 performing D2D communication determines the size of data in consideration of retransmission in D2D communication.

(flow of processing)

The difference between the example according to the reference embodiment shown in fig. 57 and the example according to the first modification of the reference embodiment shown in fig. 58 is that in the example according to the reference embodiment, step S1550 is included, whereas in the example according to the first modification of the reference embodiment, steps S1560 and S1551 are included instead of step S1550. Thus, steps S1560 and S1551 are described herein.

The terminal device 100A and the terminal device 100B determine the size of data according to whether or not the target transmission is retransmission (S1560). The flow of this process is described in detail later.

The terminal device 100A and the terminal device 100B then transmit and receive data having the determined size using the allocated radio resources for D2D communication (S1551).

Note that in the reference embodiment, as an example of the process (S1560) of deciding the size of data to be transmitted and received in D2D communication, a process similar to the example of the process (fig. 25) related to the determination of the size of data described in the first modification of the first embodiment according to the present disclosure may be applied.

The first modification of the reference embodiment is explained above. According to the first modification of the reference embodiment, even when the base station 10 which is not directly involved in D2D communication decides the size of data, data having a size in consideration of retransmission is transmitted and received in D2D communication.

<9.5. Second modification example >

Next, a second modification of the reference embodiment will be described with reference to fig. 59.

In the reference embodiment, the base station 10 is not involved directly in D2D communication, but decides the size of data to be transmitted and received in D2D communication. Thus, in the above-described reference embodiment, the base station 10 will decide the size of data to be transmitted and received in D2D communication without knowing whether there is retransmission for D2D communication between the terminal devices 100 (i.e., ACK/NACK for D2D communication). That is, the base station 10 cannot determine the size of data in consideration of retransmission in D2D communication. On the other hand, when HARQ is used, in the case of retransmission, the data is required to have the same size as that of the latest transmission.

Thus, according to the second modification of the reference embodiment, the terminal device 100 performing D2D communication feeds back information (e.g., ACK/NACK) related to retransmission for D2D communication to the base station 10, and the base station 10 performs resource control and data size determination in consideration of the presence or absence of retransmission.

(resource allocation unit 241)

As described above, the base station 10 (resource allocation unit 241) allocates radio resources for D2D communication to the terminal device 100 performing D2D communication from among radio resources controllable by the base station 10. The radio resources for D2D communication allocated in this way become radio resources (D2D resources) available for D2D communication.

In particular, in the second modification of the reference embodiment, the base station 10 (resource allocation unit 241) considers whether or not the D2D communication (i.e., target transmission) between the terminal devices 100 is retransmission to allocate radio resources for the D2D communication. For example, when the target transmission is a retransmission, radio resources are preferentially allocated for the transmission from the viewpoint of time and/or the viewpoint of the number of resources.

Note that, in the second modification of the reference embodiment, the terminal device 100 performing D2D communication feeds back information (e.g., ACK/NACK) related to retransmission for D2D communication to the base station 10. The resource allocation unit 241 then obtains the information through the wireless communication unit 220.

(data size determination section 243)

As described above, the base station 10 (data size determining unit 243) determines the size of data to be transmitted and received in D2D communication based on the radio resource information related to the radio resources allocated for D2D communication.

In particular, in the second modification of the reference embodiment, the data size decision unit 243 decides the size of data to be transmitted and received in the D2D communication, taking into account whether the D2D communication (i.e., the target transmission) between the terminal apparatuses 100 is retransmission. For example, when the target transmission is retransmission, the size of data to be transmitted and received is decided in consideration of the size of retransmission data.

Note that, in the second modification of the reference embodiment, the terminal device 100 performing D2D communication feeds back information (e.g., ACK/NACK) related to retransmission for D2D communication to the base station 10. The data size decision unit 243 then obtains the information through the wireless communication unit 220.

(flow of processing)

The difference between the example according to the reference embodiment shown in fig. 57 and the example according to the second modification of the reference embodiment shown in fig. 59 is that in the example according to the reference embodiment, steps S1520 and S1530 are included, but in the example according to the second modification of the reference embodiment, steps S1570, S1521 and S1531 are included instead of steps S1520 and S1530. Thus, steps S1570, S1521 and S1531 are described herein.

After transmission and reception of data in D2D communication (S1550), ACK/NACK is fed back between the terminal device 100A and the terminal device 100B performing D2D communication. Further, ACK/NACK is fed back from the terminal apparatus 100A and/or the terminal apparatus 100B to the base station 10 (S1570).

Further, the base station 10 (resource allocation unit 241) considers whether or not the D2D communication (i.e., target communication) between the terminal device 100A and the terminal device 100B is retransmission to allocate wireless communication for the D2D communication (S1521). The allocated radio resource becomes a radio resource (D2D resource) usable for D2D communication. The flow of this process is described later.

Further, the base station 10 (data size decision unit 243) considers whether or not the D2D communication (i.e., target communication) between the terminal device 100A and the terminal device 100B is retransmission to decide the size of data to be transmitted and received in the D2D communication (S1531). The flow of this process is described in detail later.

Note that in the second modification of the reference embodiment, as an example of the process (S1521) related to allocation of radio resources for D2D communication, a process similar to the process (fig. 27) related to resource allocation described in the second modification according to the first embodiment of the present disclosure can be applied.

Note that in the second modification of the reference embodiment, as an example of the processing (S1531) related to the determination of the data size, the processing similar to the processing (fig. 28) related to the determination of the data size described in the second modification according to the first embodiment of the present disclosure may be applied.

<9.6. Application example >

The technique according to the reference embodiment of the present disclosure is applicable to various products. For example, base station 200 may be implemented as any type of evolved node B (eNB), such as a macro eNB and a small eNB. The small eNB may be an eNB covering a smaller cell than the macro cell, such as a pico eNB, micro eNB or home (femto) eNB. The base station 200 may instead be implemented as other types of base stations, such as nodebs and Base Transceiver Stations (BTSs). The base station 200 may include a main body (also referred to as a base station apparatus) configured to control wireless communication, and one or more Remote Radio Heads (RRHs) disposed at different places from the main body. Various terminals described below may perform base station functions temporarily or semi-temporarily to function as base station 200.

(first application example)

Fig. 60 is a block diagram illustrating a first example of a schematic structure of an eNB to which the technology of the present disclosure is applied. The eNB 1900 includes one or more antennas 1910, and a base station apparatus 1920. The respective antennas 1910 and the base station apparatus 1920 may be connected to each other by RF cables.

Each antenna 1910 includes a single or multiple antenna elements (e.g., multiple antenna elements included in a MIMO antenna) for use by base station device 1920 in transmitting and receiving wireless signals. eNB 1900 may include multiple antennas 1910 as illustrated in fig. 60. For example, the plurality of antennas 1910 may be compatible with a plurality of frequency bands used by the eNB 1900, respectively. Note that fig. 60 illustrates an example in which eNB 1900 includes multiple antennas 1910, however, eNB 1900 may also include a single antenna 1910.

The base station apparatus 1920 includes a controller 1921, a memory 1922, a network interface 1923, and a wireless communication interface 1925.

The controller 1921 may be, for example, a CPU or DSP running the various functions of the higher layers of the base station apparatus 1920. For example, the controller 1921 generates data packets from data in signals processed by the wireless communication interface 1925 and transmits the generated packets through the network interface 1923. The controller 1921 may packetize data from the plurality of baseband processors, generate a packetized packet, and then transmit the generated packetized packet. The controller 1921 may have logic functions to perform such controls as radio resource control, radio bearer control, mobility management, admission control, and scheduling. The control may be performed in conjunction with a nearby eNB or core network node. The memory 1922 includes a RAM and a ROM, holds programs executed by the controller 1921, and various control data such as a terminal list, transmission power data, and scheduling data.

The network interface 1923 is a communication interface connecting the base station apparatus 1920 and the core network 1924. The controller 1921 may communicate with a core network node or another eNB through a network interface 1923. In this case, the eNB 1900 and the core network node or another eNB may be connected to each other through a logical interface (such as an S1 interface and an X2 interface). The network interface 1923 may also be a wired communication interface or a wireless communication interface for a wireless backhaul. If the network interface 1923 is a wireless communication interface, the network interface 1923 may use a higher frequency band for wireless communication than the frequency band used by the wireless communication interface 1925.

Wireless communication interface 1925 supports any cellular communication such as Long Term Evolution (LTE) and LTE-Advanced, providing wireless connectivity via antenna 1910 with terminals located within a cell of eNB 1900. The wireless communication interface 1925 may generally include, for example, a baseband (BB) processor 1926 and RF circuitry 1927. The BB processor 1926 may perform, for example, encoding/decoding, modulation/demodulation, and multiplexing/demultiplexing, and various signal processing of various layers such as L1, medium Access Control (MAC), radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP). The BB processor 1926 may have some or all of the logic functions described above in place of the controller 1921. The BB processor 1926 may be a memory holding a communication control program or a module including a processor and associated circuitry configured to execute the program. Updating the program allows the functionality of BB processor 1926 to be altered. The module may be a card or blade that is inserted into a slot of the base station apparatus 1920. Alternatively, the module may be a chip mounted on the card or blade. Meanwhile, the RF circuit 1927 may include, for example, mixers, filters, and amplifiers, which transmit and receive wireless signals through the antenna 1910.

The wireless communication interface 1925 may include a plurality of BB processors 1926 as illustrated in fig. 60. For example, the plurality of BB processors 1926 may be respectively compatible with a plurality of frequency bands used by the eNB 1900. The wireless communication interface 1925 may include a plurality of RF circuits 1927 as illustrated in fig. 60. For example, the plurality of RF circuits 1927 may be compatible with a plurality of antenna elements, respectively. Note that fig. 60 illustrates an example in which wireless communication interface 1925 includes multiple BB processors 1926 and multiple RF circuits 1927, however, wireless communication interface 1925 may also include a single BB processor 1926 or a single RF circuit 1927.

In the eNB 1900 shown in fig. 60, the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) described with reference to fig. 56 may be implemented in the wireless communication interface 1925. Further, at least a portion of these constituent elements may be implemented in the controller 1921. For example, eNB 1900 may install modules including part (e.g., BB processor 1926) or all of wireless communication interface 1925, and/or controller 1921, in which resource allocation unit 241 and data size decision unit 243 (and notification unit 245) may be implemented. In this case, the module may hold a program that allows the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245), in other words, a program that allows the processor to execute the operations of the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), and may execute the program. For another example, a program allowing the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) is installed to the eNB 1900, the wireless communication interface 1925 (e.g., the BB processor 1926), and/or the controller 1921 may execute the program. As described above, as the device including the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245), the eNB 1900, the base station device 1920, or the modules may be provided, and a program that allows the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) may be provided. Further, a readable recording medium storing the program may be provided.

(second application example)

Fig. 61 is a block diagram illustrating a second example of a schematic structure of an eNB to which the technology of the present disclosure is applied. The eNB 1930 includes one or more antennas 1940, base station equipment 1950, and RRHs 1960. The respective antennas 1940 and RRH 1960 may be connected to each other by RF cables. In addition, the base station apparatus 1950 and RRH 1960 can be connected to each other using a high-speed line such as an optical cable.

Each antenna 1940 includes a single or multiple antenna elements (e.g., multiple antenna elements included in a MIMO antenna) for use by the RRH 1960 in transmitting and receiving wireless signals. The eNB 1930 may include a plurality of antennas 1940 as illustrated in fig. 61. For example, the plurality of antennas 1940 are respectively compatible with a plurality of frequency bands used by the eNB 1930. Note that fig. 61 illustrates an example in which the eNB 1930 includes multiple antennas 1940, however, the eNB 1930 may also include a single antenna 1940.

The base station device 1950 includes a controller 1951, a memory 1952, a network interface 1953, a wireless communication interface 1955, and a connection interface 1957. The controller 1951, memory 1952 and network interface 1953 are identical to the controller 1921, memory 1922 and network interface 1923 described with reference to fig. 60.

The wireless communication interface 1955 supports any cellular communication means such as LTE or LTE-Advanced, providing wireless connectivity with terminals placed in a sector corresponding to RRH 1960 through RRH 1960 and antenna 1940. The wireless communication interface 1955 may generally include a BB processor 1956, among others. The BB processor 1956 is identical to the BB processor 1926 described with reference to fig. 60, except that it is connected to the RF circuitry 1964 of the RRH 1960 via a connection interface 1957. The wireless communication interface 1955 includes a plurality of BB processors 1956, as illustrated in fig. 61, for example, the plurality of BB processors 1956 are respectively compatible with a plurality of frequency bands used by the eNB 1930. Note that fig. 61 illustrates an example in which the wireless communication interface 1955 includes a plurality of BB processors 1956, however, the wireless communication interface 1955 may also include a single BB processor 1956.

The connection interface 1957 is an interface for connecting the base station device 1950 (wireless communication interface 1955) and the RRH 1960. The connection interface 1957 may be a communication module for connecting communication on a high-speed line of the base station device 1950 (wireless communication interface 1955) and the RRH 1960.

Further, the RRH 1960 includes a connection interface 1961 and a wireless communication interface 1963.

The connection interface 1961 is an interface that connects the RRH 1960 (wireless communication interface 1963) and the base station apparatus 1950. Connection interface 1961 may be a communication module for communication on a high-speed line.

Wireless communication interface 1963 transmits and receives wireless signals through antenna 1940. The wireless communication interface 1963 may generally include RF circuitry 1964, among others. RF circuitry 1964 may include mixers, filters, amplifiers and the like to transmit and receive wireless signals through antenna 1940. The wireless communication interface 1963 includes a plurality of RF circuits 1964 as illustrated in fig. 61. For example, the plurality of RF circuits 1964 are respectively compatible with a plurality of antenna units. Note that fig. 61 illustrates an example in which the wireless communication interface 1963 includes a plurality of RF circuits 1964, however, the wireless communication interface 1963 may also include a single RF circuit 1964.

In the eNB1930 shown in fig. 61, the resource allocation unit 241 and the data size decision 243 (and notification unit) described with reference to fig. 56 may be implemented in the wireless communication interface 1955 and/or the wireless communication interface 1963. In addition, at least a portion of these constituent elements may be implemented in the controller 1951. For example, the eNB1930 may install a module including a part (e.g., the BB processor 1956) or all of the wireless communication interface 1955, and/or the controller 1951, in which the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) may be implemented. In this case, the module may hold a program that allows the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245), in other words, a program that allows the processor to execute the operations of the radio resource information acquisition unit 161 and the data size decision unit 163 (and the notification unit 165), and may execute the program. As another example, a program allowing the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) is installed to the eNB1930, the wireless communication interface 1955 (e.g., the BB processor 1956), and/or the controller 1951 may execute the program. As described above, as the device including the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245), the eNB1930, the base station device 1950, or the modules may be provided, and a program that allows the processor to function as the resource allocation unit 241 and the data size decision unit 243 (and the notification unit 245) may be provided. Further, a readable recording medium storing the program may be provided.

The above description has explained an application example related to the base station 200 according to the reference embodiment of the present disclosure. Note that the application examples may be used as application examples related to the base station according to the embodiment of the present disclosure.

The second modification of the reference embodiment is explained above. According to the second modification of the reference embodiment, even when the base station 10 which is not directly involved in D2D communication decides the size of data, data having a size in consideration of retransmission is transmitted and received in D2D communication by using a radio resource in consideration of retransmission. As a result, the efficiency of use of radio resources can be improved.

The preferred embodiments of the present disclosure have been described above with reference to the accompanying drawings, however, the present disclosure is of course not limited to the above examples. Various changes and modifications may be suggested to one skilled in the art within the scope of the appended claims, and it should be apparent that such various changes and modifications are naturally within the skill of the present disclosure.

For example, an example of an LTE compliant communication system is illustrated, however, the present disclosure is not limited to such an example. For example, techniques according to this disclosure may be applicable to communication systems that adhere to standards other than LTE.

Further, for example, an example in which the terminal device includes a wireless communication function is described, but the present disclosure is not limited to the example. For example, the terminal device does not include a wireless communication function, but may be connected to another device (e.g., an external device, another communication device, etc.) having a wireless communication function that allows wireless communication with the base station. Further, the terminal device can communicate with the base station wirelessly by using an external device.

Further, for example, an example in which the terminal device performs wireless communication with the base station is described, but the present disclosure is not limited to this example. For example, the terminal device may communicate with the base station via a wired network. As a specific example, the terminal device may be directly connected to a LAN, or connected to another device (e.g., an external device, another communication device, etc.) capable of being connected to the LAN, and perform communication with the base station through a wired network such as a LAN, the internet, a core network, or the like. Further, for example, when communication with the base station via the wired network is enabled, the terminal device may communicate with the base station via the wired network, and when communication with the base station via the wired network is disabled, the terminal device may perform wireless communication with the base station. As another example, the terminal device need not communicate wirelessly with the base station, but may communicate with the base station only via a wired network. Note that the terminal device communicating with the base station through the wired network as described above may function as a master device in the LN.

Further, for example, an example in which the terminal device communicates with the base station is described, but the present disclosure is not limited to the example. For example, the terminal device may communicate with the core network instead of the base station. In this case, the terminal device provides information to and obtains information from the base station, for example, through a core network entity. As another example, the core network entity performs a part of the functions of the base station described above, and the terminal device provides information to and obtains information from the core network entity.

Further, the processing steps in the communication control processing and other processing in this specification are not always sequentially executed in the order illustrated in the sequence diagrams and flowcharts. For example, the processing steps in these processes may be performed in an order different from the order described as the sequence diagram and the flowchart, or the processing steps may be performed in parallel.

Further, a computer program (in other words, a computer program that allows a processor (e.g., CPU, DSP, etc.) included in a node (e.g., terminal device or base station) in this specification to function as constituent elements of the node (e.g., radio resource information acquisition unit, data size decision unit, and/or notification unit) may also be created. Furthermore, a memory holding a computer program, and a device (e.g., a processing circuit, chip or module) comprising one or more processors capable of executing the computer program may be provided.

The present technology may be configured as follows.

(1) A terminal device capable of communicating with a base station, the terminal device comprising:

an acquisition unit that acquires radio resource information on radio resources available for inter-device communication not via the base station among radio resources controllable by the base station; and

And a decision unit that decides a size of data to be transmitted and received in inter-device communication based on the radio resource information.

(2) The terminal device according to (1), further comprising:

and a notification unit that notifies the other device performing inter-device communication of size-related information related to the size.

(3) The terminal device according to (2),

wherein the size related information is informed to the other device by a transmission on a control channel for transmitting a control signal.

(4) The terminal device according to (2) or (3),

wherein the size-related information is notified to the other device by transmission over a data channel for transmitting data.

(5) The terminal device according to any one of (2) to (4),

wherein the size is one of a plurality of predetermined sizes,

wherein the size-related information is information corresponding to one of the plurality of predetermined sizes.

(6) The terminal device according to any one of (2) to (4),

wherein the size-related information is information indicating the size.

(7) The terminal device according to any one of (1) to (6),

wherein a device on a transmission side in the inter-device communication is notified of a radio resource available for the inter-device communication as a transmission resource, and a device on a reception side in the inter-device communication is notified of a radio resource available for the inter-device communication as a reception resource.

(8) The terminal device according to any one of (1) to (7),

wherein the determining unit further determines the size according to at least one of a modulation scheme and a coding scheme.

(9) The terminal device according to (8),

the modulation scheme and the coding scheme are used for inter-device communication by a device performing inter-device communication.

(10) The terminal device according to (9),

wherein when the terminal device is not a device performing inter-device communication, the deciding unit obtains information related to a channel to be used in the inter-device communication, and identifies a modulation scheme and a coding scheme based on the information.

(11) The terminal device according to (8),

wherein the modulation scheme and the coding scheme are a predetermined modulation scheme and a predetermined coding scheme when the terminal device is not a device performing inter-device communication.

(12) The terminal device according to (11),

wherein the predetermined modulation scheme is the modulation scheme with the lowest data rate among a plurality of available modulation schemes,

wherein the predetermined coding mode is the coding mode with the lowest data rate among a plurality of available coding modes.

(13) The terminal device according to any one of (8) to (12),

the decision unit calculates the number of data resources available for transmission and reception of data among wireless resources available for inter-device communication based on the wireless resource information, and decides the size based on the number of data resources and at least one of the modulation scheme and the coding scheme.

(14) The terminal device according to any one of (8) to (12),

wherein the determining unit determines, as the size, a minimum size among one or more predetermined sizes corresponding to at least one of the modulation scheme and the coding scheme, and the number of radio resources available for communication between devices, based on the radio resource information and the at least one of the modulation scheme and the coding scheme.

(15) The terminal device according to any one of (1) to (14),

wherein the radio resources available for inter-device communication are part or all of the radio resources reported by the base station as available radio resources.

(16) The terminal device according to (15),

wherein the inter-device communication is a wireless communication in a local network controlled by the terminal device,

wherein radio resources available for inter-device communication are allocated as resources for inter-device communication from radio resources reported from a base station by a terminal device.

(17) The terminal device according to (15),

wherein the radio resources available for inter-device communication are allocated by the base station as radio resources for inter-device communication, and the radio resources available for inter-device communication are reported by the base station.

(18) The terminal device according to any one of (1) to (14),

Wherein the radio resources for communication between the available devices are part or all of the radio resources estimated as available radio resources.

(19) An information processing apparatus that controls a terminal apparatus capable of communicating with a base station, the information processing apparatus comprising:

a memory for storing a predetermined program; and

a processor capable of executing the predetermined program,

wherein the predetermined program is for executing

Obtaining radio resource information on radio resources available for inter-device communication not via the base station among radio resources controllable by the base station; and

and determining the size of data to be transmitted and received in the inter-device communication according to the radio resource information.

(20) A communication control apparatus of a base station, the communication control apparatus comprising:

an allocation unit that allocates, from among radio resources controllable by the base station, radio resources for radio communication between the base station and the terminal device to the terminal device; and

a notification unit that notifies the terminal device of available radio resources among radio resources controllable by the base station,

wherein some or all of the available radio resources are used for inter-device communication not via the base station,

wherein the size of the data to be transmitted and received in the inter-device communication is not determined by the base station but by the terminal device capable of communicating with the base station.

List of reference numerals

1 communication system

10. Base station

11. Cell

20. Core network entity

21. Core network

100. Terminal equipment

161,171,181 radio resource information acquisition unit

163,173,183 data size determining unit

165,175,185 communication unit

Claims

1. A terminal device capable of communicating with a base station, the terminal device comprising:

an acquisition unit that acquires radio resource information on radio resources that can be used for inter-device communication not via the base station, among radio resources that can be controlled by the base station; and

a decision unit that decides a size of data to be transmitted and received in inter-device communication based on the radio resource information,

wherein the deciding unit calculates the number of data resources available for transmission and reception of data in radio resources available for inter-device communication based on radio resource information, calculates the maximum value of the size of data to be transmitted based on at least one of the number of data resources and modulation scheme and coding scheme, decides a column to be referred to in a candidate transport block size TBS table based on the number of data resources, decides one or more rows to be referred to in the TBS table based on the at least one of the modulation scheme and coding scheme, selects a candidate TBS of TBS table which is equal to or smaller than the maximum value among candidate TBSs corresponding to the column and the one or more rows, and selects the largest candidate TBS among the candidate TBSs as the size of data to be transmitted and received in inter-device communication.

2. The terminal device of claim 1, further comprising:

and a notification unit that notifies size-related information related to the size to another device that performs inter-device communication.

3. The terminal device according to claim 2,

4. The terminal device according to claim 2,

5. The terminal device according to claim 2,

wherein the size is one of a plurality of predetermined sizes, and

6. The terminal device according to claim 2,

wherein the size-related information is information indicating the size.

7. The terminal device according to claim 1,

wherein a device on a transmission side in the inter-device communication is notified of a radio resource that can be used for the inter-device communication as a transmission resource, and a device on a reception side in the inter-device communication is notified of a radio resource that can be used for the inter-device communication as a reception resource.

8. The terminal device according to claim 1,

9. The terminal device according to claim 8,

wherein when the terminal device is not a device performing inter-device communication, the deciding unit acquires information related to a channel to be used in the inter-device communication, and identifies a modulation scheme and a coding scheme based on the information.

10. The terminal device according to claim 1,

11. The terminal device according to claim 10,

wherein the predetermined modulation scheme is a modulation scheme with the lowest data rate among a plurality of available modulation schemes, and

wherein the predetermined coding scheme is a coding scheme with the lowest data rate among a plurality of available coding schemes.

12. The terminal device according to claim 1,

wherein the determining unit determines, as the size, a smallest size among one or more predetermined sizes corresponding to the at least one of the modulation scheme and the coding scheme and the number of radio resources available for inter-device communication, based on the radio resource information and the at least one of the modulation scheme and the coding scheme.

13. The terminal device according to claim 1,

wherein the radio resources that can be used for inter-device communication are part or all of the radio resources reported by the base station as available radio resources.

14. The terminal device according to claim 13,

wherein the inter-device communication is wireless communication in a local network controlled by the terminal device, and

wherein radio resources capable of being used for inter-device communication are allocated as radio resources for inter-device communication from among radio resources reported from a base station by a terminal device.

15. The terminal device according to claim 13,

wherein radio resources capable of being used for inter-device communication are allocated as radio resources for inter-device communication by the base station, and radio resources capable of being used for inter-device communication are reported by the base station.

16. The terminal device according to claim 1,

wherein the radio resources that can be used for inter-device communication are some or all of the radio resources that are estimates of the available radio resources.

17. An information processing apparatus that controls a terminal apparatus capable of communicating with a base station, the information processing apparatus comprising:

a memory for storing a predetermined program; and

a processor capable of executing the predetermined program,

Wherein the predetermined program is for executing

Acquiring radio resource information on radio resources which can be used for inter-device communication not via the base station among radio resources which can be controlled by the base station; and

determining a size of data to be transmitted and received in the inter-device communication based on the radio resource information,

wherein the deciding comprises: according to the radio resource information, the number of data resources which can be used for transmission and reception of data in radio resources which can be used for inter-device communication is calculated, the maximum value of the size of data to be transmitted is calculated according to at least one of the number of data resources and a modulation scheme and a coding scheme, a column to be referred to in a candidate transport block size TBS table is determined according to the number of data resources, one or more rows to be referred to in the TBS table is determined according to the at least one of the modulation scheme and the coding scheme, one or less candidate TBS of the candidate TBS corresponding to the one column and the one or more rows of the TBS table is selected, and the largest candidate TBS among the candidate TBS is selected as the size of data to be transmitted and received in inter-device communication.

18. A communication control apparatus of a base station, the communication control apparatus comprising:

a notification unit that notifies available radio resources among radio resources that can be controlled by the base station to the terminal device,

in which part or all of the available radio resources are used for inter-device communication not via a base station, and

wherein the size of data to be transmitted and received in the inter-device communication is not determined by the base station, but by the terminal device capable of communicating with the base station,

the terminal equipment calculates the number of data resources which can be used for data transmission and reception in wireless resources which can be used for inter-equipment communication according to wireless resource information, calculates the maximum value of the size of data to be transmitted according to at least one of the number of the data resources and a modulation mode and a coding mode, determines a column to be referred in a candidate Transmission Block Size (TBS) table according to the number of the data resources, determines one or more rows to be referred in the TBS table according to at least one of the modulation mode and the coding mode, selects one or more candidate TBS which is equal to or smaller than the maximum value in the candidate TBS corresponding to the column and the one or more rows in the TBS table, and selects the largest candidate TBS in the candidate TBS as the size of data to be transmitted and received in inter-equipment communication.

19. A terminal device capable of communicating with a base station, the terminal device comprising:

an acquisition unit that acquires radio resource information on radio resources that can be used for inter-device communication not via the base station, among radio resources that can be controlled by the base station;

a decision unit that decides a size of data to be transmitted and received in inter-device communication based on the radio resource information; and

a communication control unit that feeds back information on retransmission concerning inter-device communication to the base station,

20. The terminal device according to claim 19, wherein the acquisition unit acquires, from the base station, radio resources for inter-device communication allocated by the base station based on whether the inter-device communication is retransmission.

21. The terminal device of claim 20, wherein the radio resources for inter-device communication acquired from the base station include radio resources for transmission and reception of data and radio resources for transmission and reception of information related to retransmission regarding inter-device communication.

22. The terminal device of claim 21, wherein the time interval between the radio resources for transmission and reception of data and the radio resources for transmission and reception of information related to retransmission related to inter-device communication is a predetermined time interval.

23. The terminal device of claim 19, wherein the information related to retransmission regarding inter-device communication is ACK/NACK.

24. The terminal device of claim 19, wherein the feedback is through PUSCH or PUCCH.

25. An information processing apparatus that controls a terminal apparatus capable of communicating with a base station, the information processing apparatus comprising:

A memory for storing a predetermined program; and

a processor capable of executing the predetermined program,

wherein the predetermined program is for executing

Acquiring radio resource information on radio resources which can be used for inter-device communication not via the base station among radio resources which can be controlled by the base station;

determining a size of data to be transmitted and received in inter-device communication according to the radio resource information; and

information relating to retransmissions concerning inter-device communications is fed back to the base station,

26. A communication control apparatus of a base station, the communication control apparatus comprising:

wherein the allocation unit allocates the radio resource for the inter-device communication based on whether the inter-device communication is retransmission or not, according to information on retransmission regarding the inter-device communication fed back from the terminal device,